By "top PCB" I mean the one on the right side as one faces the rear of the unit (A15), and "bottom PCB" the left side one (which is also the one with the large PS caps) - A14.? Radu.?
On Sat, Sep 17, 2022 at 1:59 PM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Still working on the PS disassembly procedure.? I removed two screws at the back: And the top PCB started wiggling a bit, though it is still is attached with two inaccessible screws: As these are facing the row of shielded modules that goes from front to back of unit.? I surely hope I don't have to hollow the entire unit just to get the PS out?...? If I try from the other side, the side panel is also obstructing access to a couple of screws: The same screws seen from the inside of the unit: The bottom PCB seems to be used as a card into a header: So I assume this one may detach a little easier, though the caps are placed in their own sleeves. Are those sleeves just sliding out? Thank you for your insights! Radu.?
On Sat, Sep 17, 2022 at 1:43 PM Radu Dicher < vondicher@...> wrote: Well, further schematic errors... (thanks a ton to Ozan who straightened me on this one). C2 and C4, as they "stand" on the schematic, are opposite in polarity. The schematic is incorrect: C2 should be reversed from what the schematic says (positive on bottom). Hope this helps someone down the line.? Radu.?
On Sat, Sep 17, 2022 at 12:03 PM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I’m sorry I’ve a little mixed the capacitor reference numbers . You have >= 20v on C100 / 200 ? This is the start. I had similar problems with my power supply. So I decided to remove it and test the components one by one. I recommend this procedure because it’s dangerous to have the rest of instrument conected to a faulty power supply. There are 30% less now but can go up , no much because it’s has a great design but in my view keeps being uncomfortable .?
Is not difficult to remove the complete module .?
Regards? Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 15:21, Radu Bogdan Dicher <vondicher@...> wrote:
? To prevent any confusion, when I said I am reading 40V instead of 55V, this is between the negative legs of C2 and C4. Not at either one's legs vs ground, or over either one.? This replicates step 2 from Service Group 8 (p.8-F-1). There was no way to connect to what they're calling for ("the junction of R1 and CR2 and R2 and CR4").? Hopefully this helps with the clarity of my empirical data.? Radu.?? On Sat, Sep 17, 2022 at 11:13 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Hi Patricio, One overall conclusion is that all rails are down by about 30% (mind you, the same rate). Given they're all referenced to the +15V rail, the running assumption is that something's wrong with the?+15V regulator. I see less than 1.8V over C2. Radu.??
On Sat, Sep 17, 2022 at 10:15 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: Please note that the voltage outputs are : + - 15 vdc , 5 vdc and -5.2 Vdc … If C2 has > 40 Vdc is ok. Please take a look to power supply schematic …
 Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
Still working on the PS disassembly procedure.? I removed two screws at the back: And the top PCB started wiggling a bit, though it is still is attached with two inaccessible screws: As these are facing the row of shielded modules that goes from front to back of unit.? I surely hope I don't have to hollow the entire unit just to get the PS out?...? If I try from the other side, the side panel is also obstructing access to a couple of screws: The same screws seen from the inside of the unit: The bottom PCB seems to be used as a card into a header: So I assume this one may detach a little easier, though the caps are placed in their own sleeves. Are those sleeves just sliding out? Thank you for your insights! Radu.?
On Sat, Sep 17, 2022 at 1:43 PM Radu Dicher < vondicher@...> wrote: Well, further schematic errors... (thanks a ton to Ozan who straightened me on this one). C2 and C4, as they "stand" on the schematic, are opposite in polarity. The schematic is incorrect: C2 should be reversed from what the schematic says (positive on bottom). Hope this helps someone down the line.? Radu.?
On Sat, Sep 17, 2022 at 12:03 PM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I’m sorry I’ve a little mixed the capacitor reference numbers . You have >= 20v on C100 / 200 ? This is the start. I had similar problems with my power supply. So I decided to remove it and test the components one by one. I recommend this procedure because it’s dangerous to have the rest of instrument conected to a faulty power supply. There are 30% less now but can go up , no much because it’s has a great design but in my view keeps being uncomfortable .?
Is not difficult to remove the complete module .?
Regards? Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 15:21, Radu Bogdan Dicher <vondicher@...> wrote:
? To prevent any confusion, when I said I am reading 40V instead of 55V, this is between the negative legs of C2 and C4. Not at either one's legs vs ground, or over either one.? This replicates step 2 from Service Group 8 (p.8-F-1). There was no way to connect to what they're calling for ("the junction of R1 and CR2 and R2 and CR4").? Hopefully this helps with the clarity of my empirical data.? Radu.?? On Sat, Sep 17, 2022 at 11:13 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Hi Patricio, One overall conclusion is that all rails are down by about 30% (mind you, the same rate). Given they're all referenced to the +15V rail, the running assumption is that something's wrong with the?+15V regulator. I see less than 1.8V over C2. Radu.??
On Sat, Sep 17, 2022 at 10:15 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: Please note that the voltage outputs are : + - 15 vdc , 5 vdc and -5.2 Vdc … If C2 has > 40 Vdc is ok. Please take a look to power supply schematic …
 Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
Well, further schematic errors... (thanks a ton to Ozan who straightened me on this one). C2 and C4, as they "stand" on the schematic, are opposite in polarity. The schematic is incorrect: C2 should be reversed from what the schematic says (positive on bottom). Hope this helps someone down the line.? Radu.?
On Sat, Sep 17, 2022 at 12:03 PM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I’m sorry I’ve a little mixed the capacitor reference numbers . You have >= 20v on C100 / 200 ? This is the start. I had similar problems with my power supply. So I decided to remove it and test the components one by one. I recommend this procedure because it’s dangerous to have the rest of instrument conected to a faulty power supply. There are 30% less now but can go up , no much because it’s has a great design but in my view keeps being uncomfortable .?
Is not difficult to remove the complete module .?
Regards? Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 15:21, Radu Bogdan Dicher <vondicher@...> wrote:
? To prevent any confusion, when I said I am reading 40V instead of 55V, this is between the negative legs of C2 and C4. Not at either one's legs vs ground, or over either one.? This replicates step 2 from Service Group 8 (p.8-F-1). There was no way to connect to what they're calling for ("the junction of R1 and CR2 and R2 and CR4").? Hopefully this helps with the clarity of my empirical data.? Radu.?? On Sat, Sep 17, 2022 at 11:13 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Hi Patricio, One overall conclusion is that all rails are down by about 30% (mind you, the same rate). Given they're all referenced to the +15V rail, the running assumption is that something's wrong with the?+15V regulator. I see less than 1.8V over C2. Radu.??
On Sat, Sep 17, 2022 at 10:15 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: Please note that the voltage outputs are : + - 15 vdc , 5 vdc and -5.2 Vdc … If C2 has > 40 Vdc is ok. Please take a look to power supply schematic …
 Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
On 9/17/22 11:27 AM, walter shawlee wrote:
There is a huge assortment of HP spare parts there, let me know if you need something not shown, as I have thousands of HP parts we are trying to clear out.
I see HP LED displays on your page, but not what I'm looking for.? I'll bet that you do not have 1990-0335 nor 5082-7405 (-7415 will do in a pinch) nor 5082-7466 (looks same, different pinout?, also in a pinch) -- Jeff Woolsey {{woolsey,jlw}@jlw,first.last@{gmail,jlw}}.com Nature abhors straight antennas, clean lenses, and empty storage. "Delete! Delete! OK!" -Dr. Bronner on disk space management Card-sorting, Joel. -Crow on solitaire
|
I’m sorry I’ve a little mixed the capacitor reference numbers . You have >= 20v on C100 / 200 ? This is the start. I had similar problems with my power supply. So I decided to remove it and test the components one by one. I recommend this procedure because it’s dangerous to have the rest of instrument conected to a faulty power supply. There are 30% less now but can go up , no much because it’s has a great design but in my view keeps being uncomfortable .?
Is not difficult to remove the complete module .?
Regards? Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072
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On 17 Sep 2022, at 15:21, Radu Bogdan Dicher <vondicher@...> wrote:
? To prevent any confusion, when I said I am reading 40V instead of 55V, this is between the negative legs of C2 and C4. Not at either one's legs vs ground, or over either one.? This replicates step 2 from Service Group 8 (p.8-F-1). There was no way to connect to what they're calling for ("the junction of R1 and CR2 and R2 and CR4").? Hopefully this helps with the clarity of my empirical data.? Radu.?? On Sat, Sep 17, 2022 at 11:13 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Hi Patricio, One overall conclusion is that all rails are down by about 30% (mind you, the same rate). Given they're all referenced to the +15V rail, the running assumption is that something's wrong with the?+15V regulator. I see less than 1.8V over C2. Radu.??
On Sat, Sep 17, 2022 at 10:15 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: Please note that the voltage outputs are : + - 15 vdc , 5 vdc and -5.2 Vdc … If C2 has > 40 Vdc is ok. Please take a look to power supply schematic …
 Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
?
Lots of tek and hp goodies added to the stuff page, reduced the price on the Tek AA501A distortion analyzer package, added a nice HP power meter (436A) and sensor, and many $1 and R+D items added.
There is a huge assortment of HP spare parts there, let me know if you need something not shown, as I have thousands of HP parts we are trying to clear out. Have lots of REAR feet for hp instruments if anybody can use them, free. these go on large generators, counters, etc. Also have a lot of paper hp manuals, if you will be up this way, you are welcome to stop in and look for any you can use. not ideal for shipping, just too much weight.
?
all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.
|
To prevent any confusion, when I said I am reading 40V instead of 55V, this is between the negative legs of C2 and C4. Not at either one's legs vs ground, or over either one.? This replicates step 2 from Service Group 8 (p.8-F-1). There was no way to connect to what they're calling for ("the junction of R1 and CR2 and R2 and CR4").? Hopefully this helps with the clarity of my empirical data.? Radu.??
On Sat, Sep 17, 2022 at 11:13 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Hi Patricio, One overall conclusion is that all rails are down by about 30% (mind you, the same rate). Given they're all referenced to the +15V rail, the running assumption is that something's wrong with the?+15V regulator. I see less than 1.8V over C2. Radu.??
On Sat, Sep 17, 2022 at 10:15 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: Please note that the voltage outputs are : + - 15 vdc , 5 vdc and -5.2 Vdc … If C2 has > 40 Vdc is ok. Please take a look to power supply schematic …
 Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
Hi Patricio, One overall conclusion is that all rails are down by about 30% (mind you, the same rate). Given they're all referenced to the +15V rail, the running assumption is that something's wrong with the?+15V regulator. I see less than 1.8V over C2. Radu.??
On Sat, Sep 17, 2022 at 10:15 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: Please note that the voltage outputs are : + - 15 vdc , 5 vdc and -5.2 Vdc … If C2 has > 40 Vdc is ok. Please take a look to power supply schematic …
 Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072 On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
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Re: HP 400E sticky needle
Ok further discovery. It is peeling and that was getting in the way of the needle. Just couldn’t see it. I’ve tried the preemptive fix of applying a bit of pritt stick melted in boiling water to the edge. Used this before on gelatin legends. This sticks the flakes down with minimal risk. Fingers crossed.?
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Please note that the voltage outputs are : + - 15 vdc , 5 vdc and -5.2 Vdc … If C2 has > 40 Vdc is ok. Please take a look to power supply schematic …
 Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072
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On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
Did you set the right supply voltage on the rear panel ?, or check the switches to be sure are working ok.? Regards , Patricio?
Ing. Patricio A. GrecoTaller Aeronáutico de Reparación 1B-349Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001Gral. Martín Rodríguez 2159San Miguel (1663)Buenos AiresT:?+5411-4455-2557F:?+5411-4032-0072
toggle quoted message
Show quoted text
On 17 Sep 2022, at 12:39, Radu Bogdan Dicher <vondicher@...> wrote:
? I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.? On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
Re: HP 400E sticky needle
Thanks for the further tips. I've got an extremely clean workspace and used to work in a semi lab clean room so will take all reasonable precautions (have face shield, gloves, lint free cleaning stuff, decent plastic surface to work on available)
Will knock up a test rig with my AWG so I can slowly exercise the movement outside of the meter chassis first...
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Re: HP 400E sticky needle
Chris those are always tough and have been discussed here previously. Potentially what you are running into is a small flake of meter paint has dropped into the movement. These older meters do start to flake. Also a small bit of dirt or metal may have made its way in. It can even be a hair. Typically it requires the removal of the meter and then getting the movement out of the?case so?that all sides of the?meter can be looked at.? Then in a very clean area not the typical work bench see whats?up. Things like small bits of paper to work the grunge?out work. Nothing metal. If something actually has happened to the?jewel thats?a big problem. Do not mess with those?small screws as tempting as that is. Good luck Paul WB8TSL
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Re: VNA Calibration - Port Impedance - a late life ponder
If I understand well the question , my response is that the calibration of VNA , doesn't change the real ( physical ) impedance of the ports.
This is because you measure the real impedance at the port of a second VNA , of course if you have done the calibration OSL at the end of the cable
used to connect the second VNA .
On preliminary performance check of the 8753x VNA HP , before the SYSTEM VERIFICATION , you must measure the S11 of one port using the same VNA and the other port , calibrated OSL.?
Maurizio?
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Re: HP 400E sticky needle
Thanks for the info. I will try that later if I get a few minutes. The meter face on this isn't flaking unlike some HP stuff I've seen though which is unusual but hopefully it will dislodge anything in there anyway!
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I whipped out my longest probes - an inspired overstock purchase from maybe Anchor near SF?... - (pictures added to album, hoping they give some ideas to others get that deep inside the belly of this unit) - and I am getting 40V at the minus leg of C2 and C4 (my probing points), vs. an expected 55V. Interestingly, as soon as I power off the unit, the voltage there jumps up to about 45V, and even raises a bit more as the unit is standing powered off (5 minutes later I measure about 47V...).
Continuing my investigation.? Radu.?
On Sat, Sep 17, 2022 at 6:01 AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
|
|
Thank you all for sharing your thoughts.?
Will keep investigating this morning. I'm surprised?to not find some paragraphs on removing (each) modules in their troubleshooting sections (typically with images), which I expect from an HP manual (particularly component-level). Anyway, that concludes my whining and will go ahead and dig in there more vigorously.? Radu.?
On Sat, Sep 17, 2022 at 5:25 AM Patricio A. Greco via <patricio_greco= [email protected]> wrote: I have a HP3335A. I started to experiment problems as cpu freeze and leveling errors and I found microscopic cracks on power supply board also I removed the transistors and found an anormal slope on characteristic curves (this is thermal deterioration). Replaced the transistors and re-soldered the complete board, Also I removed the capacitors for test , these was ok . Cleaned the contacts and mounted again. After that work, instrument started to work like never. It??s very very flat, let me show you the results. I attached the response curves I measured. X Avis is logarithmic starting @1 MHz , and Y Axis is in dB relative to 1 MHz. I used 3 different methods to measure.?
Regards,?
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento?Aeronáutico de la Defensa OMAD-001
Laboratorio de Calibración ISO 17025?AREA: RF/MW?
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
Taking the assemblies loose is almost essential to troubleshooting the supply boards, but very important: You have to install a jumper to reconnect the ground - the boards are grounded through one of the brackets (the one to the bottom of the chassis if I remember correctly) and will be disconnected when it it taken loose.
Hal
|
Re: HP 400E sticky needle
Bonjour the paint and legend ink on D'Arsonval meter movements from 1970..1990 epoch can craze and a tiny flak enters the meter movement.
the close spacing between the magnet poles and armature traps a flake.
protect bench with a towel, Turn meter on its face, Tapp rear of movement lightly to dislodge the flake
if you are lucky, the errant flake will fall on the meter plastic face.
if still sticks, just Keep trying, also run the meter up and down scale
This technique has worked for me meant times
Bon courage
Jon
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Hi all,
My trusty HP 400E voltmeter has developed a sticky needle. It occasionally sticks at around 2/3 deflection and needs a tap or a large voltage change to dislodge it. The needle is not contacting the front of the meter or the legend. I've done the old "washing up liquid wipedown" to remove static but that didn't work. I checked the DC output on the back of the meter to see if it was electrical rather than mechanical but that's fine.
Does anyone have any idea how to safely approach this problem without damaging the movement?
Best regards,
Chris
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Patricio A. Greco
Froggie the Gremlin