Recent content by Retrotechie

Looks like not much on the video board but of course lots on the PSU. The smoke is very concerning - something has failed and I’d bet it is on the PSU. Have you used a voltmeter to check the voltages on the output connector? Check them all and measure both DCV and ACV. I bet you are going...

Waviness is often caused by ripple on the DC from the main rectifier cap. Often people replace these based on just capacitance (same) and voltage (same or higher) but for some applications the ripple current spec on the part needs to be considered. If the rectifier is working mains, there is...

Hmm not usually. Check to see what is shutting down. Color monitors have an x-ray protection circuit that kills the high voltage by shutting off the horizontal oscillator

Nice! I imagine that is in the vertical yoke circuit which is resonant. Great job!

First does the chip have power, +12v on. Pin 13? You must be getting horizontal so is there any 50hz sawtooth type signal on pins 11 or 10? I imagine the output you posted is pin 7 maybe? Have you checked that the deflection yoke isn’t open? If it’s ok, I would trace out the circuit and...

Yes that is a slightly older version of the schematic I sent you. The vertical amp is a KA2131.

This was in an A2M6020 AppleColor Composite monitor. I can send you the schematic if you PM me your email. The resistor R236 was blown when IC301 failed. It killed the power to IC301 (which is about +24V).

For a horizontal line I’d suspect the vertical driver. I recently had a different Apple monitor with that symptom. It was a shorted driver chip but that short took out a “fusible resistor” that was there to protect the flyback transformer. Replacing both restored the operation.

I guess I’m trying to wake up! I have no Mac experience and don’t know what software I’d need to use the Ethernet. I have lots to learn, but it is fun.

lol yeah it’s not my bag, I just love learning and fixing old electronics. This SE/30 was a freebie, all yellow, sticky, and dead. Now it’s nice! I’ll use a Blue SCSI for sure. Right now I’m using an external one. The Mac came with an Ethernet card which I’m not sure what to do with? It...

Well I iopened up the drive and the platter was stuck pretty well. I don’t think it had to do with the heads, it was the spindle just gummed up. I freed it up which took some moving back and forth. I could feel a high friction spot in the rotation. I got it spinning and ran it a couple hours...

I’ve tried bumping it with no success. I thought if the heads were stuck the drive would still spin up but maybe the heads are preventing the patter from moving somehow. I’ll open it and report back.

My SE/30 project has this drive and I’d like to see if I can get it working. It is getting good 5v and 12v but I don’t feel any spinning. It clicks twice. Any ideas?