Some old rusty SE's to fix

[falen5]

Going through some old machines from the attic that dont work

Took down and SE and have 2 logic boards

recapped the entire analog and PSU - have good voltages

ones board is dead - black screen
the others gives a display with the flashing floppy prompt - no sound

will an SE logic board work with no math co-prosessor - i see some of the pins on the dead board are really corroded

 

[Nixontheknight]

no reason why it shouldn't work without a math coprocessor, I'd check the voltages, and if everything's good there, open it and look for capacitor leakage and battery leakage

 

[ymk]

SE doesn't have an FPU. If you're talking about the BBU, it needs to be installed to boot.

 

[falen5]

SE doesn't have an FPU. If you're talking about the BBU, it needs to be installed to boot.

Took it out on the board that works and it wouldnt boot without that chip either

pins within the socket are badly corroded - tried cleaning with iso , no good

gave gentle rubbing with fine sand paper , went straight down to the copper from the corrosion

i have acetone - think ill try it with a tooth brush on the socket and the chip itself

think i can solder 2 pins on my meter probes and test for connectivity between chip legs and socket

re the rest of the board - a cap fell off as i was handleing the board - i noticed various blobs of solder on other caps - will give everything a good clean - the more i look the worse it is getting

looks like the battery leaked its destruction , how it got in the BBU is anyones guess

do those roms look OK ?

 

[dv-]

They look ok but I’d still take any socketed stuff out, spray contact cleaner around, make sure there’s no corrosion in the sockets, etc. Shouldn’t take long.

 

[falen5]

Got in there with vinegar and a tooth brush first

then washing the whole board with a mild soap - the dirt that came off it !!

a few of the pins in the BBU socket were 'back a bit' further than the other pins - carefully used pin to bring them forward , level with the other pins

looking a whole lot better

have to reinstall the cap that fell off - dry it all off with hot air and fire it up

 

[falen5]

Got the cap that fell off soldered back in

fired it up

Success

Had to spend some more time cleaning those pins within the BBU socket - fitted it and removed it a few times

Machine looks good

Now I have the other board - it works but no sound