TC Electronic problems...

[shaggy]

Hi -- yeah, all the other voltages are good. Just that brown wire is obviously low. And the batt. charge voltage seems low at 3V (if it's a 3.6V lithium).
 
I tried tracing the brn wire, thought maybe find a bad EL, but I don't have time for the shotgun approach. Again, without a schematic...

BTW, seems weird that the card in that SIMM slot in the middle of the main board has an empty (square, cpu-style, not DIP) socket (?)

Has anybody got a schematic?

--thanks

 

[shaggy]

Until you get that brown wire up to +5v I would not worry about logic/firmware.  Is the red +5v correct?

I have a dead one here and if recap does not fix it I may off it for parts...

Thanks again for the tip, which I'll follow up on soon as I get a chance. Do you think it'd be a valid test to disconnect the brown wire and power the pad with 5V from an external supply?

Good luck if you do the recap (or PM me if if you need to get rid of the carcass 8>}

(BTW, does your M2000 have an empty socket in the SIMM card?)

--cheers

 

[Whoops]

Getting the schematics would be quite usefull,
did anyone contact TC Electronics?

 

[shaggy]

Getting the schematics would be quite usefull,
did anyone contact TC Electronics?

Not exactly. Tried finding a TC service center, but seems there's none in the US. TC site has a list of independant techs. One I called offered no advice, just quoted 85 bucks for an estimate. (I forgot, or wasn't inspired enough, to ask about a schematic.)

Update: Seems I was sadly behind the times. I just read TC is now owned by Music Group (who own Behringer, among others).

Good luck getting hold of a schematic 8>[

I'm just gonna keep pokin' around...

 

[mjrippe]

OK, so you got me off my butt and I opened the TC. 

Brown wire is marked "+5v - SB" which I believe is Standby for the front panel power switch.  In other words, you turn on the main switch on the back and the PSU is on standby.  When the front panel "soft" button is pressed it turns on the outputs of the PSU (+/-15v and +5v).

My PSU was putting out +/-9v and nothing on the 5v rail.  It is only 7 8 caps in the PSU so I replaced them, with the same result.  Then I found I had missed one (hence 8) and also found a bad zener on the daughterboard.  I replaced both and then had +/-45v!!!  Perhaps I misread the value on the zener.  Anyhow, at that point I threw it in the trash.

Next test, which I should have done first, will be to hook it to my bench supply at +/-15v and +5v and ignore the SB pads.  If that works then any old switchmode or linear supply can run it (but you can't use the front panel power button).

 

[Whoops]

Next test, which I should have done first, will be to hook it to my bench supply at +/-15v and +5v and ignore the SB pads.  If that works then any old switchmode or linear supply can run it (but you can't use the front panel power button).

I was going to suggest that.
If the problem is from the smps it's easy to replace it for another one

 

[shaggy]

OK, so you got me off my butt and I opened the TC. 

Brown wire is marked "+5v - SB" which I believe is Standby for the front panel power switch.  In other words, you turn on the main switch on the back and the PSU is on standby.  When the front panel "soft" button is pressed it turns on the outputs of the PSU (+/-15v and +5v).

My PSU was putting out +/-9v and nothing on the 5v rail.  It is only 7 8 caps in the PSU so I replaced them, with the same result.  Then I found I had missed one (hence 8) and also found a bad zener on the daughterboard.  I replaced both and then had +/-45v!!!  Perhaps I misread the value on the zener.  Anyhow, at that point I threw it in the trash.

Next test, which I should have done first, will be to hook it to my bench supply at +/-15v and +5v and ignore the SB pads.  If that works then any old switchmode or linear supply can run it (but you can't use the front panel power button).

Thanks mj. I'm inspired to percevere, especially now that it looks like we're on our own.

What's your take on my low 5V SB supply? Is it not allowing bootup or something?

Oh, did you happen to notice if there's a missing chip on that SIMM card?

--cheers

 

[mjrippe]

It is possible that something is pulling down your 5v SB rail to 3v and that is preventing it from triggering when the soft power button is pressed.  If my theory is right, it won't matter when we bypass it.

My unit has no card installed either.  It is probably an expansion option.

 

[shaggy]

Thanks again for the feedback.

If it's what you say, yeah probably a bad cap, or diode or reg. Will check the main board too.

If there's any ex-TC guys out there, it'd be great to have a schematic.

--cheers

 

[mjrippe]

Ok, it works!  You do have to tie +5v to +5v SB.  My unit powered up fine and works correctly.  It draws about 700ma @ 5v at idle and about 70ma @ 15v.

Of course I can't find a PSU that will fit in the case and still have room for the IEC inlet and switch.  Cosel LDC15F-2 and TDK MTW15-51515 both fit inside.  Meanwell PT-45C will not fit, but it is much cheaper and could go external.  All of these have more than enough current.

 

[shaggy]

wow --did you use an external supply or just tie the existing 5V rails together?

edited: (duh. now I get it -- your PS still doesn't work as I recall, so you obviously used a bench supply... OK.)
Mine gives mostly correct voltages, so I'm not sure I'll have the same luck.

Thanks for the PS links too (can always bodge an extension to the rear chassis).

I got mine out again, will check after lunch.

Update: Quick test, tied the two 5Vs together briefly -- still no bootup or display.

--cheers

 

[mjrippe]

Update: Quick test, tied the two 5Vs together briefly -- still no bootup or display.

Bummer. 

Yes, I was using my bench supply.  LEDs 4 & 5 in the analog section both lit.  LEDs 1, 2, 3 to the right left (viewed from the front) did not light.  Printed near these it says "See service manual".  Are any LEDs lit on your board?

You might also disconnect the psu wires and measure all the voltages.  If you have a good PSU I would sell or trade you my working unit. 

 

[shaggy]

Hi again. Yeah, a bit disappointing so far.
When I get time I'll get the main board out and check the PS by itself. See if that 5v SB comes up; if not, look for a bad cap on the main board.. 

Didn't realize there were more than one 'diagnostic'(?)LED on the main board. There's only one that lights up and stays on (it's 2/3 to  the right and near the middle). I'll look for the others, but I can say at this point they aren't illuminating.

Def. interested in your offer, thanks. How much would you want for it? PM me if you like.

My wasted youth (and $$$) of the 90s are coming back to bite me. Checking my SV3800 and two barely used ADATs (don't laugh!) the other day. They've also decided to crap out 8>\  Probably a blessing in disguise.

 

[mjrippe]

Didn't realize there were more than one 'diagnostic'(?)LED on the main board. There's only one that lights up and stays on (it's 2/3 to  the right and near the middle). I'll look for the others, but I can say at this point they aren't illuminating.

There should be another one right next to it.  If I recall correctly the left one of the pair seems to indicate 5v and the right +/-15v.  I noticed if I turned on the 15v supply first, then the 5v it would boot up fine.  If I turned on 5v first it would not boot until 15v came on.  Both at once would probably be fine.

No shame in owning ADATS!  But no surprise they are not working either  :  I'll send you a PM about the 2000.

Mike

 

[shaggy]

Thanks Mike.

Just went over my main board and I'm sure there's only one LED. It's next to the 5V regulator chip and has a diode over it with one leg forming a TP. Maybe I have an earlier version board? (My serial no. (back panel) is 1112790, bought around 2001 I think)

I'll check my PM...

--cheers!
Dave

 

[shaggy]

Update on my M2000:

Thanks to Mike (mjrippe) for advice and help in kindly sending me his parts machine for a very fair price, I managed to get my M2000 working again.

It seems my front panel control/display pcb was the culprit, though I first tried checking the PS, then swapping the main boards.

Interestingly, the two main boards are quite different. Mikes is PC 12001-3 w/ DARC2 chip, and mine is PC 13001-4 w/ DARC3), though the chassis serial numbers aren't far apart (IIRC, mine was purchased in 2001).

The front control/display pcbs appeared identical, so I went ahead and swapped those, and viola it work 8>]

Might try putting my old main board back in at some point, w/ the newer DARC3 chip, but for my (decidedly un-musical) uses it mightn't matter that much....

--cheers guys, and thanks again
Dave

 

[Whoops]

I'm glad you were able to repair the unit.

Congrats and thanks everyone for the help

 

[drpat]

These parts are no longer available for these power supplies:
-  A1012Y
- B826
- K2545
- FCQ10A04
- F10P04
- K1118

Has anybody had any luck finding modern replacements for these parts, that work?

Especially interested in higher rated parts.

 

[Khron]

None of those look like anything too-too special. The part numbers are slightly incomplete though, i think:

- 2SA1012 (PNP, 50v 5A, Y-grade hFE 120-240)
- 2SB826 (PNP, 50v 12A)
- 2SK2545 (N-MOSFET, 600v 6A, 0.9ohm Rdson)
- FCQ10A04 (dual Schottky, common cathode, 40V 10A, isolated TO220)
- couldn't find much on the F10P04 - you sure there's no typos there? The part number "smells" like another diode, though...
- 2SK1118 (N-MOSFET, 600v 6A, 0.95ohm Rdson)

Sure, these particular part numbers may not be available, but i'd dare call them pretty much "jellybean" And you might need to do a bit of datasheet-digging to find close-enough currently-available parts, but there's no "unobtanium" there

These parts are no longer available for these power supplies:
-  A1012Y
- B826
- K2545
- FCQ10A04
- F10P04
- K1118

Has anybody had any luck finding modern replacements for these parts, that work?

Especially interested in higher rated parts.

 

[drpat]

I'm not too good at this silicon cross reference stuff. Before I hit the 'BUY' button, maybe somebody can double check the following part numbers and let me know if there's something I'm overlooking:

2N6491G for the BJT's (2SA1012 and 2SB826)

STF9N80K5 for the MOSFETS (2SK2545 and 2SK1118)

RB225T100 for the Schottky Diodes (FCQ10A04 and F10P04)