Massive T3 disaster - I need HELP!

[synthjoe]

Congrats to the improvement, good that you have an almost fully functional synth by now - enjoy!

I'd suggest to check the chips you've desoldered, maybe one or two still works and you might be able to use them in the SEQ replacement. You'd need to find a way to test the failure pattern - sysex and seq sending and reloading via MIDI seems the most plausible to me if you have no other test equipment. RAM check most definitively complains about that problem.

As to the floppy light, I'll check once I'm back from abroad (next week).

[slurpy]

Hi Synthjoe,

Well, it's really a joy to have the T3 back - over 6 months after it failed! It's also a good sense of achievement, which I certainly want to share with you!

As for the desoldered chips, they were "desoldered" with snip pliers, if you get my drift... That was the only way to get them out, without buying a rather expensive tool to allow me to apply heat to a row of 10 pins simultaneously. I have one that's good to desolder a 16 pin dual-in-line, but that is useless in this case.

All things considered, I think the thing to do is replace all 8 sequencer chips with new ones. I have 2 already, so I'll buy the other 6 and do the job.

I should also replace the EL - the old one is nearly dead. But that costs €24.50 plus shipping so... I guess I do not need a backlight all that much, since I do not use the T3 in the dark.

Anyway, please do check that floppy drive thing when you can.

Cheers,

Slurpy

[synthjoe]

Drive spins up but light is off during power on. Hope this helps.

[slurpy]

It does help. This is how my drive behaves, but somehow I was under the impression that before the PSU disaster the LED used to blink briefly at switch-on. I was probably wrong.

Thanks again for your help.

[predrag152]

Can you,please,if you have SManual in PDF,email it to me (predrag1526@yahoo.com). I couldnt find new DRAMs in SIL,so I unsoldered 5 of them from M1 motherboard,put them into T3,but problem remains (dirty strange sounds with continuous bad effects).

[synthjoe]

Does your 3/4 output work clean? Key question to answer for a proper diagnosis. Maybe you've done the soldering work for nothing...
Slurpy owns the SM I believe, maybe he'll help there - but without proper diagnosis the circuit diagram is hardly going to be of any help.

Maybe the block diagram will help troubleshooting:

[billbaker]

As a lurker on this thread I have to say that tho' I understand about a 10th of what is said and have a vague idea on about 5% more, its a kick to see you guys really hashing out a technical problem with both expertise and courtesy.

@ Slurpy - Just sorry I didn't see this thread last november when my church threw away a T-1... parts is parts; maybe a swap would have been faster than chasing the elusive RAM fault. Our T had been heavily played, replaced, ignored and abused, and put out to pasture (literally) sitting in a not quite waterproof container in a field on the church's property.

Sadly, tho' I managed to save it from the dumpster I didn't have the means to restore it, so I "donated" it to a local music tech shop where, if there is any afterlife for deserving keyboards, it was cannibalized for a good cause like keeping another T or M out of the landfill.

BB