LCII crapped the bed

[LaPorta]

So, I got this LC II a few months ago. Re-capped it. Worked perfectly. Used my Apple IIe card with it and everything. Then I put it aside for about a month.

Now, I tried to test a monitor with it. No startup chime for one. Fan and HD spin up no problem. Other than that...nothing. The screen was gray for a while...then it got distorted and the video didnt work any other time I tried to start it up. Made sure there was a good PRAM battery...same thing. Though the HD spins, there is no attempt to start from it.

Not sure where to start with this one. Any suggestions?

 

[superjer2000]

Did you recap the PSU or just the logic board?

 

[bibilit]

Did you recap the PSU

 

I agree with that, those have a high failure rate, check voltages to see if all of them are present.

Another failure point is the Egret chip, can prevent a good LB from booting, seen a hundred times.
 

 

[LaPorta]

Will check the PSU, can someone tell me which wires leading it of it are which?

 

[Scott Baret]

What exactly is the Egret chip and which Macs have it?

 

[bibilit]

IIRC, the Egret is a clock chip, will handle ADB, Pram and clock.

present in the LC series, Classic II, Classic Color, IIsi (among others) i have seen those contaminated by capacitor goo many times, and do crazy things (no boot or hard boot, chime but no display, chime and checkerboard display)

Saved a LCIII this afternoon, just removed the chip, cleaned pads and put it back again.

 

[AwkwardPotato]

I can confirm the EGRET causing issues too; on the LC series they usually sit in a nest of caps and all the leads get corroded. I've been able to get an LC II to go from a black screen to a '?' floppy screen by reflowing the leads before.

 

[LaPorta]

I will have to look into this and look at the chip...thank you.

 

[LaPorta]

I am not seeing “EGRET” on the board anywhere: what is it labeled as?

 

[LaPorta]

I had +5, +12, and something like -3.5V from the PSU.

 

[LaPorta]

Ok, let’s all get together and say “I’m a fool” together:

I forgot to pop the PRAM battery back in. Now it works.

 

[joshc]

Ok, let’s all get together and say “I’m a fool” together:

I forgot to pop the PRAM battery back in. Now it works.

I didn’t know the LC needed a PRAM battery to boot.

Does anyone know of a list somewhere of Macs which need the PRAM battery to boot?

 

[bibilit]

I didn’t know the LC needed a PRAM battery to boot

Not needed, only the 475 will need one, but only to display something (black screen if not present)

Does anyone know of a list somewhere of Macs which need the PRAM battery to boot?

Mainly the Apple II series (not the IIsi) 

Some models will not work properly also with a dead battery connected (the Powerbook G3 Pismo will not boot with a dead battery connected, but will boot if disconnected)

 

[PB145B]

I’ve actually found that the LC and LC II can be hit-or-miss on cold-boot without a PRAM battery.

I used to think mine had issues because they wouldn’t always start up, but I threw in a good battery, did some testing, and they booted every time after that.

Then I removed the battery, and they immediately started having trouble again.

 

[LaPorta]

Mine certainly will not start without a working battery in place.

 

[Scott Baret]

I have nine LC and LC II machines and all work without a PRAM battery.

 

[Cory5412]

Always nice when the problem was simpler than you thought it was.

TO add about PRAM batteries, in my experience, the LC, LC475 (I don't have a II/III), and 6100 need what is sometimes referred to as the pizzabox powertoggle if you run them without the PRAM.

Turn it on, then rapidly turn it off and back on, and then it'll come up with video.

I bought a could PRAM batteries a few years ago to avoid having to do this on my 6100, because it's my theory that this can't possibly be good for it.

Most macs with soft power don't really need a PRAM battery installed.