Buzzing noise from Apple IIe transistor?

[Anonymous]

Heyo,
Per the subject, my Apple IIe won't turn on, and there's a buzzing noise coming from the transistor. Originally, the transistor was making a clicking noise, and the power led would blink on and off, but now its gotten faster and the led doesn't turn on at all. I've read a few posts about this issue already, that it may come from a short somewhere, but I'm not such where the issue stems from. I've since taken the psu (Dynacomp 606-5001) apart and internals seem fine. Any thoughts? Thanks.

 

[bibilit]

Hi,

The blinking led is related with a shorted component, and the IIe is known for logic board diode failures.

Have a look at the bullet diodes near the PSU connector, and check for a short unit.

 

[Anonymous]

Thanks, I wasn’t sure if you meant the diodes on the psu or the motherboard, so I took photos of both. Another thing, when I lifted the psu to take photos, I heard a pop, and now the psu makes no noise when turned on. Can I hope that’s the fuse, or is this transistor dead :/

 

[bibilit]

Hi, sorry not diodes but capacitors (my fault) those are the ones on the top left of the motherboard (C9/12/15/17)

But looking at the PSU, this is not an original unit, more a clone, and most are poor in quality. I will not be surprised if it’s bad.

 

[Anonymous]

Well, touching any of the capacitors gives me a volt rating of 0. I think something’s toast. Better to just replace all four of those capacitors? Unless I’m doing something wrong, I don’t usually use multimeters

 

[bibilit]

You should look for a short, not voltage.

Using the continuity mode of the multimeter, look for any, you should not get a short between the positivé and négative side.

 

[Anonymous]

Alright. Forgive my lack of knowledge, my multimeter has an Ohm option that beeps when continuity is found. Checking C9-17 does give numbers on the screen, but there isn’t any beeping. Would that indicate anything?

 

[bibilit]

So your capacitors are ok.

Again. your PSU is not an original unit but a clone, you can use your multimeter for checking outputs from it, probably one or more are bad.

 

[Anonymous]

Heres an update, checking outputs, I’ve replaced C15 and C17, still not turning on