Re: Program to retrieve HP8920 calibration data...
Hi all,
I recently acquired a used 8920A and an 8335, both of which have some minor issues. Since I have some spare modules and board to swap around, I would be really interested in trying the calibration data download. However, the file seems to be no longer available. Can anyone help?
Regards,
Oliver
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YES, a bad cap! I fortunately heard back from Amtronix this evening. Not only does he have replacement power supplies available but he actually showed me which capacitor normally goes out. I will try replacing that cap and if that works it's party time! I've got two duplexers to tune. That's going to be interesting because I've never tuned a duplexer. My Elmer always said "Just let me do it." We'll cross that bridge after I get to the service monitor working again.
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Since he was so kind as to show me the picture I don't think he'll mind me sharing it. Just remember that if you can't get yours to work to give him a jingle and buy the board. 
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Yes, you can often get by just replacing the small capacitors on on or two of the vertical boards. I must confess that I¡¯ve done this rather than the full recap of the supply. So far, I¡¯ve been lucky.
KE6CD
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On May 18, 2021, at 4:14 PM, Alexandre Souza <alexandre.tabajara@...> wrote:
?I am not an expert in service monitors. But I repair a lot of old electroni, and not only in them, but also in my own E8285A, the problem is mostly the same - old tantalum capacitors. I'd begin searching for the yellow thingies (sometimes blue) and replacing them with good quality elcos.
Good luck! We're here to help =)
73 de PU2SEX Alexandre
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I am not an expert in service monitors. But I repair a lot of old electronics, and not only in them, but also in my own E8285A, the problem is mostly the same - old tantalum capacitors. I'd begin searching for the yellow thingies (sometimes blue) and replacing them with good quality elcos.
Good luck! We're here to help =)
73 de PU2SEX Alexandre
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I meant to add that Amtronix sells a rebuilt supply with your exchange for about $ 350.? I got one of them about 10 years ago for about $ 250 I think.? ? I later repaired 2 of the supplies in other units that would not come on by replacing a lot of the capacitors.
I don't think there are many fuses in the unit.? I have not opened one up in a good number of years.? The last time was to replace the internal 3 watt attenuator with a 100 watt one.
Ralph ku4pt
On Tuesday, May 18, 2021, 06:09:04 PM EDT, Robert <af6d.radio@...> wrote:
My unit has stayed unused for several years as I have dealt with cancer. I went to check deviation of a a repeater last night and found that it would not turn on. I turned it around to see if there was a fuse holder and of course there wasn't but I noted that there is a green LED illuminated at the bottom of the unit below the power connector. We know that power is getting to at least one stage.
I'm assuming there are numerous fuses in the unit and would appreciate knowing what to check first and where it's located. I've never opened the unit before. It might also be a bad switch because I have had a situation when even with the switch in the off position the unit turned itself on. It was quite odd.
Have a Blessed Day
_._,_,_
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Guaranteed to be bad capacitors. Attached is a repair guide for
the 8924C from the old groups I downloaded and a list of caps I
replaced in a couple of 8924 power supplies a while back. In your
particular case, it sounds like a cap on one of the little sub
PCBs which are a pain to de-solder. Its best to change all the
electrolytic caps and once done, it'll last for another 20+
years.. 73s om de chris zl1cvd
On 19/05/2021 06:50, Robert wrote:
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My unit has stayed unused for several years as I
have dealt with cancer. I went to check deviation of a a
repeater last night and found that it would not turn on. I
turned it around to see if there was a fuse holder and of
course there wasn't but I noted that there is a green LED
illuminated at the bottom of the unit below the power
connector. We know that power is getting to at least one
stage.
I'm assuming there are numerous fuses in the unit and would
appreciate knowing what to check first and where it's located.
I've never opened the unit before. It might also be a bad
switch because I have had a situation when even with the
switch in the off position the unit turned itself on. It was
quite odd.
Have a Blessed Day
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It is probably some bad?electrolytes capacitors in the power supply.? That is a well documented cause of the 8924c and others of the series not coming on.? Many old switching supplies are like that.? Sometimes heating up the capacitors with a hot air gun will get it going as long as you do not power it off.??
There may be some hints in the files section of which ones usually fail, but might as well change all the electrolytes? in the power supply.??
Better have a power screwdriver handy as you will be taking out what seems like 100 screws.? I think most of them are the star or torx type.
Once you get the case off and maybe another cover , the power supply is a module that unplugs and is easy to remove.? The wires are long enough you can lay the supply on top and test it out.? Just do not run it very long after the supply is working as it is reported the unit will over heat with out the fan of the power supply blowing.
Ralph ku4pt.??
On Tuesday, May 18, 2021, 06:09:04 PM EDT, Robert <af6d.radio@...> wrote:
My unit has stayed unused for several years as I have dealt with cancer. I went to check deviation of a a repeater last night and found that it would not turn on. I turned it around to see if there was a fuse holder and of course there wasn't but I noted that there is a green LED illuminated at the bottom of the unit below the power connector. We know that power is getting to at least one stage.
I'm assuming there are numerous fuses in the unit and would appreciate knowing what to check first and where it's located. I've never opened the unit before. It might also be a bad switch because I have had a situation when even with the switch in the off position the unit turned itself on. It was quite odd.
Have a Blessed Day
_.._,_
|
My unit has stayed unused for several years as I have dealt with cancer. I went to check deviation of a a repeater last night and found that it would not turn on. I turned it around to see if there was a fuse holder and of course there wasn't but I noted that there is a green LED illuminated at the bottom of the unit below the power connector. We know that power is getting to at least one stage.
I'm assuming there are numerous fuses in the unit and would appreciate knowing what to check first and where it's located. I've never opened the unit before. It might also be a bad switch because I have had a situation when even with the switch in the off position the unit turned itself on. It was quite odd.
Have a Blessed Day
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8920B / 8924C A2 Audio Analyzer with variable notch CLIP
anyone have the CLIP for the A2 card used in the 8920B/8924C ?
This has the variable notch filter option.
The one for the 8920A is close but have an issue surrounding the variable filter.
The variable filter is a lot more complex than the simple 1khz notch.
Interesting that this version is standard on the 8920 and 8924 and if the older one is installed you get a self test error 1000.
You also get this if the I/O card is disconnected or not installed.? ? The Variable Notch A2 and I/O are not really optional and looks like they need to be there to get past the self test error.?
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Re: 8924C video out using a GBS-8200 to vga questions
Follow up: well I finally go to test it and it worked OK except I noticed after about 30 minutes it was dimmer. If I kill power and restart it it come back on bright. It never went away totally so I¡¯ll add the resistors and see if that helps.?
another thing if I used the menu on the board to center adjust size etc I lose the settings once power is removed. So not sure how to save the settings. ?
thanks Bill N7OQ
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Re: 8924C video out using a GBS-8200 to vga questions
Don't forget to post your results here =)
Em 19/04/2021 19:54, William Verstelle escreveu:
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Ok thanks I¡¯ll try none first then add if needed. Got chip already mounted on a board today so will try is soon.
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Re: 8924C video out using a GBS-8200 to vga questions
Ok thanks I¡¯ll try none first then add if needed. Got chip already mounted on a board today so will try is soon.?
thanks Guys!?
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Re: 8924C video out using a GBS-8200 to vga questions
I didn't use them, and it worked...
Em 18/04/2021 22:02, William Verstelle escreveu:
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The 50k resistors, how critical is that value, I have 47k and 56k will either of these work? I guess I could use 2x100k if needed.
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Re: 8924C video out using a GBS-8200 to vga questions
either will work.
On 19/04/2021 13:02, William Verstelle
wrote:
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The 50k resistors, how critical is that value, I have 47k and
56k will either of these work? I guess I could use 2x100k if
needed.?
Bill N7OQ
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Re: 8924C video out using a GBS-8200 to vga questions
The 50k resistors, how critical is that value, I have 47k and 56k will either of these work? I guess I could use 2x100k if needed.?
Bill N7OQ
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Re: 8924C video out using a GBS-8200 to vga questions
Wow again, great information, I get my lm-1881 Thursday or wed. Will let you know how it works out, thanks everyone,
Bill N7OQ
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Re: 8924C video out using a GBS-8200 to vga questions
To use the GBS-8200 converter with the hp-8924c service monitor to use with an external VGA monitor.
Obtain:
50 K ohm SMD resistors 4 required
LM1881N IC sync seperator .1 UF capacitor--2 required 680 K? ohm resistor
To be mounted on the GBS8200 board will be 4 SMD 50 K ohm resistors.?? Without the resistors the display will seem to work for? about 30 seconds and fade out. That is what it did for me.
On the LM1881 connect pin 1 to the # 4 (gray wire) pin of the 8 pin RGBS input connector. Pin 2 to a .1 UF capacitor and then to? the Green input of the 8 pin RGBS connector? A wire from that junction goes to the input from the 8924C. Pin 4 to ground. Pin 6 has a .1 UF and 680 K resistor in parallel to ground. Pin 8 goes to 5 volts. Pins 3,5,7 are not used.
The 4 SMD 50 K ohm resistors are soldered across capacitors 29,32,33, and 36 on the? GBS8200 board.? They are in a row between the 3 pots and an IC.
This will provide a green video output to a VGA monitor.
On Sunday, April 18, 2021, 02:05:33 AM EDT, William Verstelle <bverstelle@...> wrote:
Hi group, I want to replace the CRT monitor in my 8924 and bought a GBS-8200 board. Well I saw a picture where they plugged it into the green (Y) rca jack on the 8200 board and this worked to a degree but the display was black and white and the right hand side was cut off. I tried the vga/ega connector without a sync and nothing,?reading another article and blog they used a lm1881 sync separator to extract the V and H syncs. ?So here are my questions
1. does the composite video on a HP 9824c ?have the Sync pulses in it? ?(The article was for a different HP analyzer)
2. The schematic shows the V and H sync pulses are already at the CRT monitor plug can I use these pulses?
3. it there any other way to connect or modify the board to make it work?
It seems like a lot of the info was lost in the move from Yahoo to here like a lot of my other groups so I¡¯m getting bit and pieces. The reason I want to replace the crt monitor is because it has a lot of burn in on the screen and it is only time before I have problems with it. Plus LCD screens are easier to read on my old eyes.?
thanks, Bill N7OQ
?
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Re: 8924C video out using a GBS-8200 to vga questions
My guide:
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---8<---Corte aqui---8<---
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Re: 8924C video out using a GBS-8200 to vga questions
Bill
Here are a couple of old things i saved re getting the GBS-8200
workings with 8924 from the old Yahoo groups.
There is also one on power supply repair plus some notes on power
supply caps I replaced a while back - maybe useful for ordering
replacements.
73s om de chris zl1cvd
On 18/04/2021 18:05, William Verstelle
wrote:
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Hi group, I want to replace the CRT monitor in my 8924 and
bought a GBS-8200 board. Well I saw a picture where they plugged
it into the green (Y) rca jack on the 8200 board and this worked
to a degree but the display was black and white and the right
hand side was cut off. I tried the vga/ega connector without a
sync and nothing,?reading another article and blog they used a
lm1881 sync separator to extract the V and H syncs. ?So here are
my questions
1. does the composite video on a HP 9824c ?have the Sync pulses
in it? ?(The article was for a different HP analyzer)
2. The schematic shows the V and H sync pulses are already at
the CRT monitor plug can I use these pulses?
3. it there any other way to connect or modify the board to make
it work?
It seems like a lot of the info was lost in the move from Yahoo
to here like a lot of my other groups so I¡¯m getting bit and
pieces. The reason I want to replace the crt monitor is because
it has a lot of burn in on the screen and it is only time before
I have problems with it. Plus LCD screens are easier to read on
my old eyes.?
thanks, Bill N7OQ
?
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8924C video out using a GBS-8200 to vga questions
Hi group, I want to replace the CRT monitor in my 8924 and bought a GBS-8200 board. Well I saw a picture where they plugged it into the green (Y) rca jack on the 8200 board and this worked to a degree but the display was black and white and the right hand side was cut off. I tried the vga/ega connector without a sync and nothing,?reading another article and blog they used a lm1881 sync separator to extract the V and H syncs. ?So here are my questions
1. does the composite video on a HP 9824c ?have the Sync pulses in it? ?(The article was for a different HP analyzer)
2. The schematic shows the V and H sync pulses are already at the CRT monitor plug can I use these pulses?
3. it there any other way to connect or modify the board to make it work?
It seems like a lot of the info was lost in the move from Yahoo to here like a lot of my other groups so I¡¯m getting bit and pieces. The reason I want to replace the crt monitor is because it has a lot of burn in on the screen and it is only time before I have problems with it. Plus LCD screens are easier to read on my old eyes.?
thanks, Bill N7OQ
?
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Alexandre Souza
Chris, ZL1CVD