Recent content by powellb

Great! I am hoping that the spare plus board I ordered will work out. It sounds like a very difficult endeavor due to the ferrite coil inside. While not precise, making something similar I believe is hard...

I have this same problem. I have tested/replaced the resistors and caps in that horizontal control circuit to no effect. It is common for the L2 inductor to break internally (the very fragile internal ferrite coil). It seems the only fix is to find a donor board and replace the inductor. I have...

Sorry, just saw your post. Sorry, just saw your post. I am confident (not 100%) that the L2 slug inductor has internally broken (weak ferrite coil), so nothing is controlling the horizontal width. I removed and tested the resistors and capacitors tied to that circuit with everything in spec. I...

It is hard to see with your eye (your picture is likely masked in that black area), but on the side facing the analog board is a hex shaped opening a little bigger than the hole you are seeing light through. You need to use your hex driver (if metallic, adjust while off, test, repeat). I have a...

You are correct, but I had no choice. The horizontal control is different than others in terms of voltage danger (still don't do it), but rotating the coil to set it with my plastic tool was having no effect. So, I inserted a metallic to see if that might be the cause (from some old CRT tidbits...

I have been working trying to figure this out, and it seems that something is amiss with the "width" control circuit. The width adjustment is a coil within a plastic tube. When I put a metal hex driver in there to turn it, the screen width gets much smaller, and I can adjust it. However, once I...

Over the weekend, I left the Mac SE/30 running for #Marchintosh, but came to it this morning and the built-in monitor has gone completely strange. First, I could only see a picture when turning the front (and interior) brightness settings to max for both; whereas, it used to be normally...

BTW, thinking about it, I was thinking about my NeXT Cube Power Supply where I had to desolder a number of pins of a small PCB. Sorry for the confusion. I've done too many power supplies in the last 18 months. Do you have a load on the supplies? I don't recall with this supply, but most...

Yes, I desoldered and removed it. Then I recapped the psu and the small board and reinstalled it as part of reassembly. I didn’t have my desoldering gun at the time, so I just used desoldering braid and it soaked it up nicely allowing the pins to slide out. Good luck!

I was replacing caps in a monitor and other things so I figured I would do the 7600 psu while I was doing everything. It was working before, but I wanted to refurbish it and check joints. All redone and should be good for the rest of my life! im not a psu person, but the output from the bridge...

Just to follow up: I ordered metal-film E96 845k resistors and put the PS back together. Everything is working perfectly. Nice to have that PS rebuilt. Thanks again for checking for me!

Actually thanks to user obsolete, they determined that the value is 845K ohms. Hope that helps anyone who comes across this.

Thank you very much, this is a great help! I was tracing through the diagram to try to figure out what is was doing. The output of bridge rectifier goes into positive side of capacitor C1, but that also goes through R41 that then goes to R42, where I lose what is happening. I really appreciate...

Resurrecting an old thread here. I posted in another forum without luck. I am also rebuilding this PS, and in the image above from Imsi4126, you can see that below C1 is a large blob of glue. I removed that glue when replacing C1 because it was really holding it down. Later, I realized that R41...

Rather the pinging an old thread about this power supply, I am asking broadly. All, I am refurbishing the power supply on my PowerMac 7600. When replacing C2, I had to remove all of the white adhesive around it, and it turned out there was a resistor in there that was pulled from its leads...