Grundig GV-250 PSU fuse burns out repeatedly?

hugocarmo · #1 01-19-2023, 04:28 AM

Hi everyone.
I have the following problem.
I have a Grundig GV-250 VCR which has not been used for over 10 years. When I turned it on, the fuse of the PSU burned out, after being replaced it burned again, I ended up verifying that I had the bridge rectifier and the mosfet in short, I ended up replacing it, and I replaced all the electrolytics of the PSU. However, it started to behave strangely, as I will show you in the video that I will attach as a link.
In short, I ended up replacing all the ICs on the power supply CNY17G, TDA4605, TL431, TDA8137, TL082CP, AN3824K, L2720, this on the upper part of the power supply board. On the soldering part, I replaced the bas20 switching diode.
Always with the same result. I ended up disassembling the video head and removing the plate that is soldered to the motor, then I replaced all the electrolytics, and IC AN3814K. Same result.
I don't know what to do anymore, can someone help me?
I also enclose the Service Manual for this model.
P.S.- At the end of the video, as you can see, the video recorder is working normally.

Video Link:
https://vimeo.com/790579424

Service Manual Link:
https://drive.google.com/file/d/17es...usp=share_link

Thanks in advance,
Compliments,
Hugo do Carmo.

latreche34 · #2 01-19-2023, 10:11 AM

You don't just go on the blind and replace components unless you tested and have a good reason, Having said that, have you cleaned the mode switch?

hugocarmo · #3 01-19-2023, 10:20 AM

Thanks for your reply.
Yes I did, Was one of the first things I did, the mode switch is soldered, took it off and cleaned with contact cleaner.

Regards,

Hugo.

latreche34 · #4 01-19-2023, 10:22 AM

Look up 23-1920 error code in the manual. What does it do anyway? It's not clear from the video what you are trying to do or what buttons you are pressing.

hugocarmo · #5 01-19-2023, 10:32 AM

Hi.
Thank You for your answer.
19:20 is the clock time.
The 23 code I dont know what means and in the manual nothing is refering to that code.
The buttons I touched were the jog shuttle wich turns on the vcr and changes tv channels, then the power off button.

Regards,

Hugo.

Quote:

Originally Posted by latreche34

Look up 23-1920 error code in the manual. What does it do anyway? It's not clear from the video what you are trying to do or what buttons you are pressing.

hugocarmo · #6 01-20-2023, 08:08 AM

Hi!!
Just fixed the problem!
It was a bad TDA4605, the one I replaced was new but not good, don´t know why.
Replaced it and now everything working as expected.
I want to thank You all for your answers.

Best regards,

Hugo.

hodgey · #7 01-20-2023, 10:48 AM

Coll that you sorted it!

Just wanted to note that I have a very similar mono one, might be from the same lineup (Grundig VS900), and it had a WIMA X capacitor that went poof when I started using it. It's more known to happen with RIFA branded ones which you might be familiar with since it seems you have some experience with electronics repair but WIMA also had a similar type. The one in the GV250 service manual has the same part number (though idk if the actual part is the same.) as the one in my VS900 it looks like. So, it might be worth checking if it has cracks in it and/or swapping it out if it's the type that goes poof (yellow-ish epoxy encased thing).

It did also have some bad electrolytics causing it to not start properly but that was more expected. Also interested that Grundig put the impedance roller on this, panasonic only did that for the SVHS versions of the VCRs with the panasonic G/G2 mechanisms that grundig/philips also used in a few vcrs in this period.

hugocarmo · #8 01-27-2023, 03:55 AM

Quote:

Originally Posted by hodgey

Coll that you sorted it!

Just wanted to note that I have a very similar mono one, might be from the same lineup (Grundig VS900), and it had a WIMA X capacitor that went poof when I started using it. It's more known to happen with RIFA branded ones which you might be familiar with since it seems you have some experience with electronics repair but WIMA also had a similar type. The one in the GV250 service manual has the same part number (though idk if the actual part is the same.) as the one in my VS900 it looks like. So, it might be worth checking if it has cracks in it and/or swapping it out if it's the type that goes poof (yellow-ish epoxy encased thing).

It did also have some bad electrolytics causing it to not start properly but that was more expected. Also interested that Grundig put the impedance roller on this, panasonic only did that for the SVHS versions of the VCRs with the panasonic G/G2 mechanisms that grundig/philips also used in a few vcrs in this period.

Hi Hodgey
Are you talking about these? Lol!
It took them off as opened the PSU!!
I´ve seen movies that they burn a lot!

Thank You!

enois · #9 02-19-2023, 07:31 AM

Quote:

Originally Posted by hodgey

Just wanted to note that I have a very similar mono one, might be from the same lineup (Grundig VS900), and it had a WIMA X capacitor that went poof when I started using it.

Quote:

Originally Posted by hugocarmo

Hi Hodgey
Are you talking about these? Lol!
It took them off as opened the PSU!!
I´ve seen movies that they burn a lot!

This happened to me too! In a GV-250 not working, recovered from a friend, and left standing for more 15 years.
It was not the primary fault, but after a couple of hours I leave in stand by, it started emit an intense burning smell and the Wima X2 capacitor burnt out.

Thanks hugocarmo for the service manual: the 220uF 25V electrolytic capacitors acid leaking removed the PCB silkscreen, I marked the polarity, but with service manual I feel more comfortable...

To hodgey: a similar problem happened to me in a Philips Turbodrive VR632 power supply, not sure if same capacitor brand, but I remember semi transparent yellow-ish capacitor.
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hodgey · #10 02-19-2023, 08:29 AM

Hehe yeah, just saw the same thing happen with those caps with video99 on youtube when fixing a Grundig GV 680 SVHS deck. There is a fair bit of overlap and shared parts/designs between the Grundig and (european) Philips vcrs, at least up to the late 90s. Not sure what the exact relationship between the companies were.

Looks like the same brand, though it's more about the way they were made than the specific brand I think.

Quote:

Originally Posted by hugocarmo

Hi Hodgey
Are you talking about these? Lol!

Forgot to reply but yeah, it's those. It will work without them though ideally they should be replaced with new ones since they are there to filter out noise going back out onto the mains power, at least if it's equipment that will be used a bit. (Look up X and Y capacitors if you aren't already familiar with it) Every power supply is going to have some variation X caps and Y caps so it's possible to salvage something from a scrap power supply board if you don't want spend money on new ones.