Digest for sci.electronics.repair@googlegroups.com - 1 update in 1 topic

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Usenetist <carg121@usenet.com>: Jan 27 11:48PM -0500

I have a Behringer power mixer (PMX1000) that features a DSP effects
module with a 2-digit 7-seg display.
 
The DSP module is a daughterboard with legend on it DPM5 PCB304030REVI
 
Photo here
https://community.musictribe.com/discussion/products/24/34/324663/dpm5-effects-module-error-d2
 
It has a TMS57002 DSP and P80C32SBAA microcontroller and EDO DRAM (2 off
HY514404).
 
On power up, the display shows F1 for about 100ms and then stays on d2
 
I only have a schematic for the main mixer board, which basically
contains just the 7-seg displays, so I am assuming the d2 code
originates from the software running on the DSP board.
 
I have seen some threads suggesting replacing the DRAM fixed it, but I
have tried that (once) with no effect.
 
Does anybody have a schematic or any official info on what the d2 code
specifically means?
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Digest for sci.electronics.repair@googlegroups.com - 1 update in 1 topic

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legg <legg@nospam.magma.ca>: Jan 23 09:10AM -0500


>Also requires replacement lamp and stirring reflector
>motor.
 
>RL
 
This thing is in working order and programmes.
 
It had some gunk penetrating the stiring motor
couplig shaft area that had carbonized and would cause
visible arcing, until the polyproplylene components
were scraped completely clean.
 
It's just inconvenient and unsafe to run without
confirmation of an obvious countdown in the run
time.
 
If I brush my thumb across the display the major
' 1 ' and 'ON' segments display, regardless of
operating state or cooking time. These fade
gradually.
 
RL
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Digest for sci.electronics.repair@googlegroups.com - 1 update in 1 topic

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Digest for sci.electronics.repair@googlegroups.com - 2 updates in 1 topic

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Chuck <chuck23@dejanews.net>: Jan 17 03:19PM -0600

On Tue, 16 Jan 2024 22:28:09 -0500, Usenetist <carg121@usenet.com>
wrote:
 
>>> Thank you in advance for your help.
 
>> Those old Akais had lots of electrolytic caps that get weak with age. Try heating the signal boards with a heat gun to see if the color returns. If it does, you're going to have to recap that unit if you intend to keep it.
 
>Can you explain the heat gun technique for bad caps... how does it work?
When you heat up a bad cap, the ESR goes down and the capacitance goes
up and sometimes the problem goes away. You then replace the cap you
were heating when the symptom went away. I would suggest buying a
cheap esr meter on EBay. It is a quicker and more certain way of
finding bad capacitors.
"ohg...@gmail.com" <ohger1s@gmail.com>: Jan 18 06:48AM -0800

On Tuesday, January 16, 2024 at 10:28:13 PM UTC-5, Usenetist wrote:
> On 1/9/24 12:24, ohg...@gmail.com wrote:
 
> > Those old Akais had lots of electrolytic caps that get weak with age. Try heating the signal boards with a heat gun to see if the color returns. If it does, you're going to have to recap that unit if you intend to keep it.
 
> Can you explain the heat gun technique for bad caps... how does it work?
 
When I suspect a lazy/weak/ electrolytic capacitor as the cause of a failure, I take my heat gun and warm up the board in question. I get the board pretty hot but not hot enough to melt connectors, ribbons, or indeed the shrink wrap on the capacitors. If the device now performs correctly or even if the symptom changes, an electrolytic becomes a strong suspect. MOST weak capacitors improve with heat, but you'll find the occasional one that actually responds better to cold, but that's as about as rare or more so as finding an open silicon diode (most short). The heat may also affect defective semiconductors so if heat fixes it, it could still be anything on the board that's become heat sensitive, but most circuits that come back to life with applied heat will have a bad capacitor(s).
 
Once I identify weak dried out capacitors with heat, I'll either shotgun the device if it's old and I want it to be long term reliable, or I'll take out my ESR meter and go over the board when the board cools down if it's a board with a crapload of caps where shotgunning is time consuming. One way to get all the weak ones identified is to put the board in question in the refrigerator (or outside if it's cold), as even capacitors that work well at room temperature and not causing any immediate issues may fail at very cold temps. Capacitors that are in good condition won't be bothered by the cold, so it's a good way to ferret out the ones that will fail next. Caps that work at room temp but not in cold temps are on borrowed time.
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Digest for sci.electronics.repair@googlegroups.com - 1 update in 1 topic

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Usenetist <carg121@usenet.com>: Jan 16 10:28PM -0500


>> Hello! I have read all your posts and you are absolutely right. Unfortunately, there are always such people who qualify the helpers. Well, I also learned a lot from what was written here, at the hobby level I repair a VHS VCR, which also has no color. The type is AKAI VS-3. I repaired the servo part and the power part did not work. Now it starts, plays, spins. The head drum was also bad, so I put in a new original one. Now there is a picture, but it is black and white and jumps a little. I can't adjust the tape path any better. I would really appreciate it if you could advise me. I checked the video pcb, all12, pb12 are fine. Unfortunately, I don't have a test cassette, although I tried to make a color bar cassette and check it at the test points, but I didn't have much success.
>> Thank you in advance for your help.
 
> Those old Akais had lots of electrolytic caps that get weak with age. Try heating the signal boards with a heat gun to see if the color returns. If it does, you're going to have to recap that unit if you intend to keep it.
 
Can you explain the heat gun technique for bad caps... how does it work?
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Notificação de retirada do blog do Blogger

12:20 PM Penedão 0 comments
Olá,

O Google foi notificado de que seu blog supostamente inclui conteúdo que viola os direitos de terceiros e as leis de outros países. O conteúdo infrator, incluído no final desta mensagem, não está mais disponível. Para mais informações sobre a remoção e como isso afeta seu blog, visite https://support.google.com/blogger/bin/answer.py?l=en&answer=2402711.

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Digest for sci.electronics.repair@googlegroups.com - 2 updates in 2 topics

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Retro Deck <asuspropad@gmail.com>: Jan 11 07:56AM -0800

> > Hello! I have read all your posts and you are absolutely right. Unfortunately, there are always such people who qualify the helpers. Well, I also learned a lot from what was written here, at the hobby level I repair a VHS VCR, which also has no color. The type is AKAI VS-3. I repaired the servo part and the power part did not work. Now it starts, plays, spins. The head drum was also bad, so I put in a new original one. Now there is a picture, but it is black and white and jumps a little. I can't adjust the tape path any better. I would really appreciate it if you could advise me. I checked the video pcb, all12, pb12 are fine. Unfortunately, I don't have a test cassette, although I tried to make a color bar cassette and check it at the test points, but I didn't have much success.
> > Thank you in advance for your help.
> Those old Akais had lots of electrolytic caps that get weak with age. Try heating the signal boards with a heat gun to see if the color returns. If it does, you're going to have to recap that unit if you intend to keep it.
 
Thanks! I will try this way as well.
Chuck <chuck23@dejanews.net>: Jan 10 12:52PM -0600

On Tue, 9 Jan 2024 22:38:09 -0800 (PST), Ben Lu
>> Chuck
>> --
>This is a old thread, so I don't know if you are still looking for the solution. If so, I'm very familiar with this drive and have fixed more than a hundred units.
Thanks for your advice but I had cataracts at the time and I tanked
the mechanism while disassembling it.
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Digest for sci.electronics.repair@googlegroups.com - 2 updates in 2 topics

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Ben Lu <camsnparz88@gmail.com>: Jan 09 10:38PM -0800

On Monday, January 10, 2022 at 6:31:35 AM UTC-8, Chuck wrote:
> functions. Any tips would be greatly appreciated. Thanks.
> Chuck
> --
This is a old thread, so I don't know if you are still looking for the solution. If so, I'm very familiar with this drive and have fixed more than a hundred units.
"ohg...@gmail.com" <ohger1s@gmail.com>: Jan 09 09:24AM -0800

> Hello! I have read all your posts and you are absolutely right. Unfortunately, there are always such people who qualify the helpers. Well, I also learned a lot from what was written here, at the hobby level I repair a VHS VCR, which also has no color. The type is AKAI VS-3. I repaired the servo part and the power part did not work. Now it starts, plays, spins. The head drum was also bad, so I put in a new original one. Now there is a picture, but it is black and white and jumps a little. I can't adjust the tape path any better. I would really appreciate it if you could advise me. I checked the video pcb, all12, pb12 are fine. Unfortunately, I don't have a test cassette, although I tried to make a color bar cassette and check it at the test points, but I didn't have much success.
> Thank you in advance for your help.
 
Those old Akais had lots of electrolytic caps that get weak with age. Try heating the signal boards with a heat gun to see if the color returns. If it does, you're going to have to recap that unit if you intend to keep it.
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Digest for sci.electronics.repair@googlegroups.com - 2 updates in 2 topics

8:41 AM Penedão 0 comments
Retro Deck <asuspropad@gmail.com>: Jan 08 11:03PM -0800

Charles Lucas ezt írta (2022. július 17., vasárnap, 1:15:21 UTC+2):
> integrated circuits and circuits out there and different ways to actuate them (a resistor,a diode, a transistor, or cap, etc...), so it depends on
> the design of the circuit. If I have a model number, I can tell you what pins to check to verify correct operation. I have been a tech. for 32
> years and not all circuits are designed the same. The initial information is generalized as a guide. If you want something more specific, please provide a model number or an FCC ID number. God Bless you.
 
Hello! I have read all your posts and you are absolutely right. Unfortunately, there are always such people who qualify the helpers. Well, I also learned a lot from what was written here, at the hobby level I repair a VHS VCR, which also has no color. The type is AKAI VS-3. I repaired the servo part and the power part did not work. Now it starts, plays, spins. The head drum was also bad, so I put in a new original one. Now there is a picture, but it is black and white and jumps a little. I can't adjust the tape path any better. I would really appreciate it if you could advise me. I checked the video pcb, all12, pb12 are fine. Unfortunately, I don't have a test cassette, although I tried to make a color bar cassette and check it at the test points, but I didn't have much success.
Thank you in advance for your help.
"Peter W." <peterwieck33@gmail.com>: Jan 08 09:42AM -0800

https://newsgroupservers.net/usenet-basics/usenet-newsgroup-reader/
 
https://en.wikipedia.org/wiki/List_of_Usenet_newsreaders
 
https://www.itpro.com/infrastructure/network-internet/368088/six-of-the-best-usenet-newsgroup-readers
 
Not rocket science.
 
Peter Wieck
Melrose Park, PA
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