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Hi all,
I finally found the time to repair the Type 106 I bought back almost a year ago¡
A few months ago I had offline help from 2 very nice people here.
That thing had shorts everywhere. A few blown transistors, 3 out of 5 shorted bridge rectifiers, burned resistors, shorted and opened diodes, the whole shebang¡. In other words, it drove me crazy¡
It¡¯s now finally back from the dead, and working quite well, except for a few voltage issues.
3 voltages are referenced to what they call the ¡°A SUPPLY¡±: +150 +/- 15V, -150V +/- 15V, -20V +/- 2V.
All check within specs at +153.7, -150.72, and although the -20V reads a bit low at 18.73V, it¡¯s still ok.
However, 1 is referenced to chassis ground, and it should be + and - 10V +/- 1.5V, but I read very high at +16.73V and -16.59V.
The manual tells you to check the voltages, but not how to correct them when they¡¯re not within specs.
Can anyone help? Thanks.
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On Fri, Dec 17, 2021 at 07:56 PM, Stephen wrote:
However, 1 is referenced to chassis ground, and it should be + and - 10V +/-
1.5V, but I read very high at +16.73V and -16.59V.
The manual tells you to check the voltages, but not how to correct them when
they¡¯re not within specs.
Can anyone help? Thanks.
That's a very simple circuit with two main causes for your problem, although a bit surprising the two separate supplies are both bad: 1. D213 and D216 open. Check if they carry +10V and -10V aginst GND. 2. Q213 and Q217 shorted between C and E or open B. Depending on how the instrument is constructed (I don't have one), some connections could be open. Should be easy to check with your DMM. The voltages are shown in the Manual. Raymond
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Hi Stephen,
My first thought is that the series regulators on +/-10 are not regulating.
Most obvious issue would be Q213 and Q217 are shorted, and/or D213 and D216 are open.
Check the 27VAC at the transformer, and verify that you see about 14VAC between each side and Ground.
Given all the problems you already found and fixed, perhaps the unit was exposed to a "catastrophic" event, such as being powered by 230V when the switch was set to 115V.
Pete
|
Also some of the supplies in this unit are unregulated. Check the
transformer for correct line voltage. The line voltage have moved up I the
world sence these were built it is normal for some of the supplies to be
elevated here in the US these were made for 115vac. And they are now seeing
125 vac at the line. This will elevate some of the supplies. It might be
fine.
Eric
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On Fri, Dec 17, 2021, 2:17 PM saipan59 (Pete) <saipan1959@...> wrote: Hi Stephen,
My first thought is that the series regulators on +/-10 are not regulating.
Most obvious issue would be Q213 and Q217 are shorted, and/or D213 and
D216 are open.
Check the 27VAC at the transformer, and verify that you see about 14VAC
between each side and Ground.
Given all the problems you already found and fixed, perhaps the unit was
exposed to a "catastrophic" event, such as being powered by 230V when the
switch was set to 115V.
Pete
|
My bad. I wasn¡¯t probing the right places. Instead of checking voltages between chassis ground and directly at both emitters, I probed between ground and + C215/ C218. According to the schematic, this should be the same. But apparently not¡
|
Hi Pete.
They are not shorted. I have checked all the transistors in the power supply with a dedicated transistor checker. They are fine and within specs.
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What about D213 and D216? You can simply measure the voltage at the cathode of D213, and the anode of D216 (or at the Base of the associated transistor, if that's easier to get to). Should be around 10V.
If the diodes are open, the output voltage would be just about what you are seeing (around 16 to 18V).
It pretty much HAS TO BE either the transistors, the Zener diodes, or an external short across the transistors (both of them).
Pete
|
One other note: Even though the two rails are named "+10" and "-10", note that the schematic shows that the REAL values are +9.1 and -9.1.
Pete
|
The voltages taken directly at the emitters read + and - 9.7V. All within specs.
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Yes, you¡¯re right. But weirdly enough the +/- 9.1 are also mentioned at the capacitors. Which is misleading.
That¡¯s why I expected that when I checked there, but nope¡
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Ah, so your earlier "my bad" message meant to say that nothing is actually wrong with the +/-10 rails. Got it.
However, regarding:
"Instead of checking voltages between chassis ground and directly at both emitters, I probed between ground and + C215/ C218. According to the schematic, this should be the same. But apparently not"
You MUST get the same values at the Emitters and at +C215 and -C218 ! If you don't, you've got a measurement problem, OR those caps are not actually connected like they should be.
Note that those rails *may* appear to work fine, even if C215 and C218 are missing...
Pete
|
On Fri, Dec 17, 2021 at 11:00 AM, saipan59 (Pete) wrote:
What about D213 and D216? You can simply measure the voltage at the cathode of
D213, and the anode of D216 (or at the Base of the associated transistor, if
that's easier to get to). Should be around 10V.
If the diodes are open, the output voltage would be just about what you are
seeing (around 16 to 18V).
It pretty much HAS TO BE either the transistors, the Zener diodes, or an
external short across the transistors (both of them).
Pete
Yes, but no. Everything is fine. As you understood, I was not probing at the right place. I was misled by the +/- 9.1V beneath the capacitors, so I probed there because it was an easy access.
|
Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise outputs? I think one or two of mine are bad. The +OUTPUT works but not the -OUTPUT. Input to the two diodes on the -OUTPUT side looks okay but at the junction between the two, the signal is not correct and the output is not correct at all.
I've never seen diodes constructed like these before and don't expect I'll find direct replacements but am wondering could be used as replacements.
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message ----- From: "saipan59 (Pete)" <saipan1959@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 4:24:27 PM
Subject: Re: [TekScopes] Type 106 Ah, so your earlier "my bad" message meant to say that nothing is actually wrong
with the +/-10 rails. Got it.
However, regarding:
"Instead of checking voltages between chassis ground and directly at both
emitters, I probed between ground and + C215/ C218. According to the
schematic, this should be the same. But apparently not"
You MUST get the same values at the Emitters and at +C215 and -C218 ! If you
don't, you've got a measurement problem, OR those caps are not actually
connected like they should be.
Note that those rails *may* appear to work fine, even if C215 and C218 are
missing...
Pete
|
Based on the fast-rise circuitry of the 106 and PG506 being similar and having similar specs, you would seem to have several good Si-Schottky candidates. A few that come to mind are:
MBD101
BAV17
HSMS-282x (15V breakdown makes these an upgrade over the stock diodes)
These have slightly higher capacitance than the GaAs originals, but it's not enough to matter.
I'm sure others will chime in shortly with their recommendations.
-- Cheers
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
toggle quoted message
Show quoted text
On 12/17/2021 16:11, n4buq wrote: Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise outputs? I think one or two of mine are bad. The +OUTPUT works but not the -OUTPUT. Input to the two diodes on the -OUTPUT side looks okay but at the junction between the two, the signal is not correct and the output is not correct at all.
I've never seen diodes constructed like these before and don't expect I'll find direct replacements but am wondering could be used as replacements.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "saipan59 (Pete)" <saipan1959@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 4:24:27 PM
Subject: Re: [TekScopes] Type 106
Ah, so your earlier "my bad" message meant to say that nothing is actually wrong
with the +/-10 rails. Got it.
However, regarding:
"Instead of checking voltages between chassis ground and directly at both
emitters, I probed between ground and + C215/ C218. According to the
schematic, this should be the same. But apparently not"
You MUST get the same values at the Emitters and at +C215 and -C218 ! If you
don't, you've got a measurement problem, OR those caps are not actually
connected like they should be.
Note that those rails *may* appear to work fine, even if C215 and C218 are
missing...
Pete
|
Thanks, Tom. The existing diodes are tiny glass(?) cylinders with metal ends that clip into small holders (much like the old fashioned clip-in fuses). I suppose I'll be doing some plumbing for whatever I find to replace them.
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message ----- From: "Tom Lee" <tomlee@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 7:14:57 PM
Subject: Re: [TekScopes] Type 106 Based on the fast-rise circuitry of the 106 and PG506 being similar and
having similar specs, you would seem to have several good Si-Schottky
candidates. A few that come to mind are:
MBD101
BAV17
HSMS-282x (15V breakdown makes these an upgrade over the stock diodes)
These have slightly higher capacitance than the GaAs originals, but it's
not enough to matter.
I'm sure others will chime in shortly with their recommendations.
-- Cheers
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 12/17/2021 16:11, n4buq wrote:
Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise
outputs? I think one or two of mine are bad. The +OUTPUT works but not the
-OUTPUT. Input to the two diodes on the -OUTPUT side looks okay but at the
junction between the two, the signal is not correct and the output is not
correct at all.
I've never seen diodes constructed like these before and don't expect I'll find
direct replacements but am wondering could be used as replacements.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "saipan59 (Pete)" <saipan1959@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 4:24:27 PM
Subject: Re: [TekScopes] Type 106
Ah, so your earlier "my bad" message meant to say that nothing is actually wrong
with the +/-10 rails. Got it.
However, regarding:
"Instead of checking voltages between chassis ground and directly at both
emitters, I probed between ground and + C215/ C218. According to the
schematic, this should be the same. But apparently not"
You MUST get the same values at the Emitters and at +C215 and -C218 ! If you
don't, you've got a measurement problem, OR those caps are not actually
connected like they should be.
Note that those rails *may* appear to work fine, even if C215 and C218 are
missing...
Pete
|
On second look, the DAV17 comes in a DO-35 package. I think I can solder some small-diameter tubing to the leads right up against the diode's body and clip it in to the existing holders.
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message ----- From: "n4buq" <n4buq@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 8:54:38 PM
Subject: Re: [TekScopes] Type 106 Thanks, Tom. The existing diodes are tiny glass(?) cylinders with metal ends
that clip into small holders (much like the old fashioned clip-in fuses). I
suppose I'll be doing some plumbing for whatever I find to replace them.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Tom Lee" <tomlee@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 7:14:57 PM
Subject: Re: [TekScopes] Type 106 Based on the fast-rise circuitry of the 106 and PG506 being similar and
having similar specs, you would seem to have several good Si-Schottky
candidates. A few that come to mind are:
MBD101
BAV17
HSMS-282x (15V breakdown makes these an upgrade over the stock diodes)
These have slightly higher capacitance than the GaAs originals, but it's
not enough to matter.
I'm sure others will chime in shortly with their recommendations.
-- Cheers
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 12/17/2021 16:11, n4buq wrote:
Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise
outputs? I think one or two of mine are bad. The +OUTPUT works but not the
-OUTPUT. Input to the two diodes on the -OUTPUT side looks okay but at the
junction between the two, the signal is not correct and the output is not
correct at all.
I've never seen diodes constructed like these before and don't expect I'll find
direct replacements but am wondering could be used as replacements.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "saipan59 (Pete)" <saipan1959@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 4:24:27 PM
Subject: Re: [TekScopes] Type 106
Ah, so your earlier "my bad" message meant to say that nothing is actually wrong
with the +/-10 rails. Got it.
However, regarding:
"Instead of checking voltages between chassis ground and directly at both
emitters, I probed between ground and + C215/ C218. According to the
schematic, this should be the same. But apparently not"
You MUST get the same values at the Emitters and at +C215 and -C218 ! If you
don't, you've got a measurement problem, OR those caps are not actually
connected like they should be.
Note that those rails *may* appear to work fine, even if C215 and C218 are
missing...
Pete
|
"BAV17" (typo).
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message ----- From: "n4buq" <n4buq@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 9:00:57 PM
Subject: Re: [TekScopes] Type 106 On second look, the DAV17 comes in a DO-35 package. I think I can solder some
small-diameter tubing to the leads right up against the diode's body and clip
it in to the existing holders.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "n4buq" <n4buq@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 8:54:38 PM
Subject: Re: [TekScopes] Type 106 Thanks, Tom. The existing diodes are tiny glass(?) cylinders with metal ends
that clip into small holders (much like the old fashioned clip-in fuses). I
suppose I'll be doing some plumbing for whatever I find to replace them.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Tom Lee" <tomlee@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 7:14:57 PM
Subject: Re: [TekScopes] Type 106 Based on the fast-rise circuitry of the 106 and PG506 being similar and
having similar specs, you would seem to have several good Si-Schottky
candidates. A few that come to mind are:
MBD101
BAV17
HSMS-282x (15V breakdown makes these an upgrade over the stock diodes)
These have slightly higher capacitance than the GaAs originals, but it's
not enough to matter.
I'm sure others will chime in shortly with their recommendations.
-- Cheers
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 12/17/2021 16:11, n4buq wrote:
Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise
outputs? I think one or two of mine are bad. The +OUTPUT works but not the
-OUTPUT. Input to the two diodes on the -OUTPUT side looks okay but at the
junction between the two, the signal is not correct and the output is not
correct at all.
I've never seen diodes constructed like these before and don't expect I'll find
direct replacements but am wondering could be used as replacements.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "saipan59 (Pete)" <saipan1959@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 4:24:27 PM
Subject: Re: [TekScopes] Type 106
Ah, so your earlier "my bad" message meant to say that nothing is actually wrong
with the +/-10 rails. Got it.
However, regarding:
"Instead of checking voltages between chassis ground and directly at both
emitters, I probed between ground and + C215/ C218. According to the
schematic, this should be the same. But apparently not"
You MUST get the same values at the Emitters and at +C215 and -C218 ! If you
don't, you've got a measurement problem, OR those caps are not actually
connected like they should be.
Note that those rails *may* appear to work fine, even if C215 and C218 are
missing...
Pete
|
I took a look at the tekwiki page and saw those custom packages. Pretty cool looking -- like scaled-down old-style point-contact "catwhisker" detectors from the days of crystal radio.
If it were my unit, I'd remove the holders and just solder the replacements directly onto the board to avoid all the parasitics that would come from trying to make the replacement diodes physically emulate the original ones. But that's me.
The manual has some pages on small differences between the GaAs and Si diode circuits, by the way, so you might want to take a look at that info if you haven't already.
-- Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
toggle quoted message
Show quoted text
On 12/17/2021 18:54, n4buq wrote: Thanks, Tom. The existing diodes are tiny glass(?) cylinders with metal ends that clip into small holders (much like the old fashioned clip-in fuses). I suppose I'll be doing some plumbing for whatever I find to replace them.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Tom Lee" <tomlee@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 7:14:57 PM
Subject: Re: [TekScopes] Type 106
Based on the fast-rise circuitry of the 106 and PG506 being similar and
having similar specs, you would seem to have several good Si-Schottky
candidates. A few that come to mind are:
MBD101
BAV17
HSMS-282x (15V breakdown makes these an upgrade over the stock diodes)
These have slightly higher capacitance than the GaAs originals, but it's
not enough to matter.
I'm sure others will chime in shortly with their recommendations.
-- Cheers
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
On 12/17/2021 16:11, n4buq wrote:
Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise
outputs? I think one or two of mine are bad. The +OUTPUT works but not the
-OUTPUT. Input to the two diodes on the -OUTPUT side looks okay but at the
junction between the two, the signal is not correct and the output is not
correct at all.
I've never seen diodes constructed like these before and don't expect I'll find
direct replacements but am wondering could be used as replacements.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "saipan59 (Pete)" <saipan1959@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 17, 2021 4:24:27 PM
Subject: Re: [TekScopes] Type 106
Ah, so your earlier "my bad" message meant to say that nothing is actually wrong
with the +/-10 rails. Got it.
However, regarding:
"Instead of checking voltages between chassis ground and directly at both
emitters, I probed between ground and + C215/ C218. According to the
schematic, this should be the same. But apparently not"
You MUST get the same values at the Emitters and at +C215 and -C218 ! If you
don't, you've got a measurement problem, OR those caps are not actually
connected like they should be.
Note that those rails *may* appear to work fine, even if C215 and C218 are
missing...
Pete
|
I bet an anti-static wriststrap is in order when working with these tiny junctions.? ? ? ? ? Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
toggle quoted message
Show quoted text
-------- Original message --------From: Tom Lee <tomlee@...> Date: 12/17/21 8:53 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Type 106 I took a look at the tekwiki page and saw those custom packages. Pretty cool looking -- like scaled-down old-style point-contact "catwhisker" detectors from the days of crystal radio.If it were my unit, I'd remove the holders and just solder the replacements directly onto the board to avoid all the parasitics that would come from trying to make the replacement diodes physically emulate the original ones. But that's me.The manual has some pages on small differences between the GaAs and Si diode circuits, by the way, so you might want to take a look at that info if you haven't already.-- Cheers,Tom-- Prof. Thomas H. LeeAllen Ctr., Rm. 205350 Jane Stanford WayStanford UniversityStanford, CA 94305-4070 12/17/2021 18:54, n4buq wrote:> Thanks, Tom.? The existing diodes are tiny glass(?) cylinders with metal ends that clip into small holders (much like the old fashioned clip-in fuses).? I suppose I'll be doing some plumbing for whatever I find to replace them.>> Thanks,> Barry - N4BUQ>> ----- Original Message ----->> From: "Tom Lee" <tomlee@...>>> To: "tekscopes" < [email protected]>>> Sent: Friday, December 17, 2021 7:14:57 PM>> Subject: Re: [TekScopes] Type 106>> Based on the fast-rise circuitry of the 106 and PG506 being similar and>> having similar specs, you would seem to have several good Si-Schottky>> candidates. A few that come to mind are:>>>> MBD101>> BAV17>> HSMS-282x (15V breakdown makes these an upgrade over the stock diodes)>>>> These have slightly higher capacitance than the GaAs originals, but it's>> not enough to matter.>>>> I'm sure others will chime in shortly with their recommendations.>>>> -- Cheers>> Tom>>>> -->> Prof. Thomas H. Lee>> Allen Ctr., Rm. 205>> 350 Jane Stanford Way>> Stanford University>> Stanford, CA 94305-4070>> >>>> On 12/17/2021 16:11, n4buq wrote:>>> Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise>>> outputs?? I think one or two of mine are bad.? The +OUTPUT works but not the>>> -OUTPUT.? Input to the two diodes on the -OUTPUT side looks okay but at the>>> junction between the two, the signal is not correct and the output is not>>> correct at all.>>>>>> I've never seen diodes constructed like these before and don't expect I'll find>>> direct replacements but am wondering could be used as replacements.>>>>>> Thanks,>>> Barry - N4BUQ>>>>>> ----- Original Message ----->>>> From: "saipan59 (Pete)" <saipan1959@...>>>>> To: "tekscopes" < [email protected]>>>>> Sent: Friday, December 17, 2021 4:24:27 PM>>>> Subject: Re: [TekScopes] Type 106>>>> Ah, so your earlier "my bad" message meant to say that nothing is actually wrong>>>> with the +/-10 rails. Got it.>>>>>>>> However, regarding:>>>> "Instead of checking voltages between chassis ground and directly at both>>>> emitters, I probed between ground and + C215/ C218.? According to the>>>> schematic, this should be the same.? But apparently not">>>> You MUST get the same values at the Emitters and at +C215 and -C218 ! If you>>>> don't, you've got a measurement problem, OR those caps are not actually>>>> connected like they should be.>>>> Note that those rails *may* appear to work fine, even if C215 and C218 are>>>> missing...>>>>>>>> Pete>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>
|
Yes, indeed, that's very good advice, Jim. Even if you don't pop the diodes outright, they can become very leaky.
-- Cheers,
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
toggle quoted message
Show quoted text
On 12/17/2021 21:02, Jim Ford wrote: I bet an anti-static wriststrap is in order when working with these tiny junctions.? ? ? ? ? Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Tom Lee <tomlee@...> Date: 12/17/21 8:53 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Type 106 I took a look at the tekwiki page and saw those custom packages. Pretty cool looking -- like scaled-down old-style point-contact "catwhisker" detectors from the days of crystal radio.If it were my unit, I'd remove the holders and just solder the replacements directly onto the board to avoid all the parasitics that would come from trying to make the replacement diodes physically emulate the original ones. But that's me.The manual has some pages on small differences between the GaAs and Si diode circuits, by the way, so you might want to take a look at that info if you haven't already.-- Cheers,Tom-- Prof. Thomas H. LeeAllen Ctr., Rm. 205350 Jane Stanford WayStanford UniversityStanford, CA 94305-4070 12/17/2021 18:54, n4buq wrote:> Thanks, Tom.? The existing diodes are tiny glass(?) cylinders with metal ends that clip into small holders (much like the old fashioned clip-in fuses).? I suppose I'll be doing some plumbing for whatever I find to replace them.>> Thanks,> Barry - N4BUQ>> ----- Original Message ----->> From: "Tom Lee" <tomlee@...>>> To: "tekscopes" <[email protected]>>> Sent: Friday, December 17, 2021 7:14:57 PM>> Subject: Re: [TekScopes] Type 106>> Based on the fast-rise circuitry of the 106 and PG506 being similar and>> having similar specs, you would seem to have several good Si-Schottky>> candidates. A few that come to mind are:>>>> MBD101>> BAV17>> HSMS-282x (15V breakdown makes these an upgrade over the stock diodes)>>>> These have slightly higher capacitance than the GaAs originals, but it's>> not enough to matter.>>>> I'm sure others will chime in shortly with their recommendations.>>>> -- Cheers>> Tom>>>> -->> Prof. Thomas H. Lee>> Allen Ctr., Rm. 205>> 350 Jane Stanford Way>> Stanford University>> Stanford, CA 94305-4070>> >>>> On 12/17/2021 16:11, n4buq wrote:>>> Speaking of a 106, anyone know anything about the GaAs diodes in the Fast Rise>>> outputs?? I think one or two of mine are bad.? The +OUTPUT works but not the>>> -OUTPUT.? Input to the two diodes on the -OUTPUT side looks okay but at the>>> junction between the two, the signal is not correct and the output is not>>> correct at all.>>>>>> I've never seen diodes constructed like these before and don't expect I'll find>>> direct replacements but am wondering could be used as replacements.>>>>>> Thanks,>>> Barry - N4BUQ>>>>>> ----- Original Message ----->>>> From: "saipan59 (Pete)" <saipan1959@...>>>>> To: "tekscopes" <[email protected]>>>>> Sent: Friday, December 17, 2021 4:24:27 PM>>>> Subject: Re: [TekScopes] Type 106>>>> Ah, so your earlier "my bad" message meant to say that nothing is actually wrong>>>> with the +/-10 rails. Got it.>>>>>>>> However, regarding:>>>> "Instead of checking voltages between chassis ground and directly at both>>>> emitters, I probed between ground and + C215/ C218.? According to the>>>> schematic, this should be the same.? But apparently not">>>> You MUST get the same values at the Emitters and at +C215 and -C218 ! If you>>>> don't, you've got a measurement problem, OR those caps are not actually>>>> connected like they should be.>>>> Note that those rails *may* appear to work fine, even if C215 and C218 are>>>> missing...>>>>>>>> Pete>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>
|
Raymond Domp Frank
saipan59 (Pete)