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-   -   1994 RCA VR528 blows fuses (http://www.videokarma.org/showthread.php?t=276466)

pac.attack76 02-27-2024 07:23 PM

1994 RCA VR528 blows fuses
 
On first check, I noticed the 250v 1.6a fuse was blown. Replaced with same and blew again. Noticed there was some residue in the power area where something had dropped in. Cleaned and dried. Let sit for a couple days and tried again with same type fuse. Blew again. I'm betting whatever leaked in, took something out but not sure where to start.

Blast 02-27-2024 08:05 PM

Computer says I worked on 28 of those from 1995-1998. Based on serial numbers looks like build dates of mid 1994 to early 1995. About half of them repaired under warranty.

That unit was made by IVP, a joint venture of Thomson Consumer Electronics and Toshiba.

The FCC ID# is G95538194 and the service manual was titled VR528 and may also have included GE model VG4039 (although I'll bet THOSE are rare!).

My notes say that about half of those 28 had two shorted "clock diodes" that was taking out the fuse. Locations: DP026 & DP027. RCA p/n 219242 (may have been individual diodes. Or not) or 231734 (may have been a "kit" of diodes. And something else? Or not).

My cross reference says that 1N4007 may be a possible sub for the 219242, as well as ECG 125 and SK 3080.

I can't even remember the fix, the "clock diodes" or where they were even located.

But, good luck with the fix!

If you'd send some really good quality photos it might spur my memory (or the computer) further.

pac.attack76 02-27-2024 09:03 PM

I'll get some pics up tomorrow. There's also a sticker inside indicating a power supply repair was done in 95.

pac.attack76 02-27-2024 09:34 PM

Let me know if these work.

Blast 02-29-2024 07:46 PM

Thanks for the photos. I see DP026 and DP027. Do you?

Notice how DP027 has been "rerouted" to join another diode. That triggers a memory about a modification that may have been involved. Maybe that was part of the 231734 "kit".

So.... Are said diodes shorted?

pac.attack76 02-29-2024 07:47 PM

Quote:

Originally Posted by Blast (Post 3255911)
Thanks for the photos. I see DP026 and DP027. Do you?

Notice how DP027 has been "rerouted" to join another diode. That triggers a memory about a modification that may have been involved. Maybe that was part of the 231734 "kit".

So.... Are said diodes shorted?

Yes, I noticed those. I haven't tested yet.

pac.attack76 02-29-2024 07:49 PM

Do I need to remove them to test or can they stay in?

Blast 02-29-2024 08:08 PM

For now they can stay in.

pac.attack76 02-29-2024 08:09 PM

Quote:

Originally Posted by Blast (Post 3255914)
For now they can stay in.

Ok I'll go check them

pac.attack76 02-29-2024 08:16 PM

Looks like DP026 is open. If I used the right setting lol��
I'm not sure if this is right

Blast 02-29-2024 08:41 PM

https://www.youtube.com/watch?v=mMXDa5hVzXA

pac.attack76 02-29-2024 08:47 PM

Yeah, that's the thing, mine doesn't have the OL. Mine just shows a 1 off to the left and if I get a reading, it's 3 or 4 numbers to the right. Both show a reading one way and just the 1 in the other direction

Blast 03-01-2024 08:57 PM

I have no idea what that post means. Likely because I'm not familiar with the brand/type/model of meter you're using.

I can tell you that diodes typically short; they don't open.

pac.attack76 03-01-2024 09:18 PM

Quote:

Originally Posted by Blast (Post 3255938)
I have no idea what that post means. Likely because I'm not familiar with the brand/type/model of meter you're using.

I can tell you that diodes typically short; they don't open.

It's just a $15 cheapo from Walmart I bought a few years ago. I'll take pics of the readings so you can see

old_tv_nut 03-02-2024 03:42 PM

Quote:

Originally Posted by pac.attack76 (Post 3255919)
Both show a reading one way and just the 1 in the other direction

This sounds very much like good diodes - conducting one way and open circuit (resistance out of range on your meter) the other way.
Is the reading "1" what you get with the meter disconnected from everything?


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