68kMLA Classic Interface

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Grape iMac DV Revival
Posted by: LaPorta on 2024-01-23 08:41:07
Did they have a sale on pink markers at the store? 😛
Posted by: LaPorta on 2024-01-23 08:42:53
Seriously though, do you do all the caps at once, or one at a time? In my practice, I generally do one at a time (at least on through-hole caps) so I can match up the caps lead for lead one at a time. Easier than removing them all at once.
Posted by: CYB3RBYTE on 2024-01-23 10:10:28
Yeah, I do like the pink marker, helps me to remember which ones I've done and which I haven't, it's an old mechanics trick. I do one at a time unless two manage to come out at once using the twist off method.
Posted by: LaPorta on 2024-01-23 10:38:21
Just bad luck then. I once blew one off an analog board that way. Is it possible if you scrub that resistor that you could still read the value?
Posted by: CYB3RBYTE on 2024-02-02 10:48:36
Does anyone know what resistor goes in R992 on this analog board is? I have a photo of it prior to it being damaged, looks to be a 5.6 kOHM? Don’t want to order the wrong one and then have a problem.

IMG_1487.jpeg
Posted by: Cory5412 on 2024-02-13 18:33:57
My apologies for the delay, I've removed a couple things to keep this going.

Good luck with your iMac @CYB3RBYTE - it looks like a beautiful system!
Posted by: 68kPlus on 2024-02-17 03:45:00
@CYB3RBYTE

You might have luck with schematics, but I'm not sure how many are around for slot-loading iMacs
Posted by: KillerKong on 2024-03-01 12:40:58
Does anyone know what resistor goes in R992 on this analog board is? I have a photo of it prior to it being damaged, looks to be a 5.6 kOHM? Don’t want to order the wrong one and then have a problem.
Hi, that is definitely a 5k6 resistor.
Posted by: 68kPlus on 2024-03-15 17:28:25
Hey @CYB3RBYTE, any luck with this yet?
Posted by: CYB3RBYTE on 2024-03-21 07:15:36
I found the resistor I need to order, however I'll be holding off on reassembly / repair of this machine until the clear display bezels from the kickstarter project become available. I suppose around may / June I may attempt reassembly but to be honest I have several other projects in line first at this point.
Posted by: mitchW on 2024-03-23 14:41:03
My condolences. Btw, why did you attempt to do a full recap anyways? Were there any problems that looked like there were bad capacitors? I deal with 70 year old radios and TVs sometimes, and I almost always replace just one cap and then test. I only do a full recap on few sets that I had restored dozens of.

And for those, there are full service manuals (with schematics) available...
Posted by: GRudolf94 on 2024-03-25 22:46:13
My condolences. Btw, why did you attempt to do a full recap anyways? Were there any problems that looked like there were bad capacitors? I deal with 70 year old radios and TVs sometimes, and I almost always replace just one cap and then test. I only do a full recap on few sets that I had restored dozens of.

And for those, there are full service manuals (with schematics) available...
70 year old radios aren't plagued by low-ESR electrolytics going out of wonk in a 20 year period. The failure modes are quite different.
Posted by: mitchW on 2024-03-27 17:14:18
That's true. But I would really like to see how bad the original caps were ESR wise.
If that was a eMac (the one with known capacitor disease) or iMac G5, then a full recap (including the PSU) would be totally in order. I had iMac G5s that didn't boot into OS (just froze) that had just one capacitor blown on the mainboard.

Btw,
Few weeks ago, I had a friend phone me for advice, he just fully recapped a 2004 Samsung SyncMaster CRT 17-inch monitor as the picture was soft (slightly of focus, especially on the edges, and somewhat dim). Recapping made no difference to the picture quality whatsoever, and he was quite mad since he spent about $40 on capacitors and about 4 hours of his time.

Long story short, the culprits were both the worn out CRT, and slightly out-of-adjustment focus control on the flyback. I turned the focus control and made it almost perfect, but the image was still dim, and increasing the G2 (Screen) control made it just completely blur out. I said that it looks like the CRT is weak.
Later we took it to another friend of mine that used to own a TV repair shop not so long ago, and he put it on a CRT tester, which showed it was quite tired. He did a CRT cathode cleaning, it made it just a tiny bit better, later he tried with rejuvenation, but it didn't help.
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