SWR Spellbinder Blue Power Amp Schematic

[bobloblaws]

Ok. I had thought that connector carried AC to the other board. If it's the +/-25VDC, and the other board derives it's voltages from there, then yes that may be why the fuses blew. You could replace those and power up only the ICE module and see if they hold.

That sounds reasonable.

As for the green FMIC board my options are fix or replace. If I were to end up going with the latter I'm still unclear on how I could locate this module.

Anybody?

[vintagekiki]

I'm still unclear on how I could locate this module.

If you think about module schematic, look posts ...

https://music-electronics-forum.com/showthread.php?t=49232&p=532731&viewfull=1#post532731

https://music-electronics-forum.com/showthread.php?t=49232&p=532964&viewfull=1#post532964

[g1]

If you think about module schematic, look posts ...

I think he means the other module, called 'aux supply' on the schematic. 0076036000

[chrisdski]

Did anyone snag the Spellbinder Blue service manual mentioned earlier in this thread? If yes, please post it.

[bobloblaws]

Did anyone snag the Spellbinder Blue service manual mentioned earlier in this thread? If yes, please post it.

Here you go Spellbinder Blue Svc Man.pdf

[chrisdski]

Perfect. Thanks much.

[chrisdski]

can someone identify what T3 and T4 are in terms of replacement parts? I googled the numbers, nothing came up. Proprietary Fender parts?

[The Dude]

According to the schematic:

T3 =

*XFMR ANCILLARY P.S. TUBE PWR

T4 =

*XFMR ANCILLARY P.S. +/-15V

And, also note:
*Non-serviceable part. Replace complete parent assembly.

Those are both transformers- one for B+ to the tube and the other is for the +/-15V supply. It's unlikely they are the problem as transformers rarely fail. Check B+, +/-15V and see if they are working. Check tube plate and look for 15V regulators. The schematic above doesn't show power supply.

[chrisdski]

Mine just died. I ordered the proper ICE power supply/amp board. Fender does not have the ancillary power board anymore, so no replacement. I’ll check all the Q transistors on the ancillary board.

[chrisdski]

Update. So the 400ma fuses on the ICEpower board that supply the ancillary power board were blown. I replaced them and I now have the +/- 25v that supplies the ancillary board. Going thru the transistors and diodes of the ancillary board I took the following readings. I will replace D7 and Q6. What about the other diode readings in circuit? Not sure if I may be getting a charged capacitor or another loop in the circuit. Recommendations/advice?

[g1]

Lift one end of the questionable parts and re-measure. Be very careful as it will be double sided board.

[chrisdski]

Is there a technique to desoldering double sided boards? I use desoldering wick, but it seems difficult to get a clean hole easily.

[nosaj]

I have found a desoldering gun is best. But what i do is take some 63/37 solder and wet each joint with solder first(I guess Flux would do the same) but I use what I have.
nosaj

[g1]

Is there a technique to desoldering double sided boards? I use desoldering wick, but it seems difficult to get a clean hole easily.

Chip Quik is very helpful for this.

[chrisdski]

Update. Successful repair. The problem originated in the ancillary power supply board. This is a proprietary Fender design and to date no schematic is available. This ancillary board is powered from the ICEpower 50ASX2BTL main power/amp board using a +/-25 volt feed. There are two 250v/400mA fuses (F100/101) on the ICEpower that feed P103 to the ancillary board. Check these fuses first, mine were blown. I replaced the fuses and restored the +/-25 volt feed. Next I check all the power Transistors and diodes on the ancillary board. I found D7 was no resistance both ways, and D6 was suspect in the board. I replaces both (D7 was definitely shot upon measuring when pulled). Q6 measured bad in the board (it’s next to D7) and was replaced. All the other transistors measured ok in the board. C9 was split at the top so I replaced it even though it measured ok. My measurements for tested components are on an earlier picture (I didn’t replace any other diodes because they measured all the same in circuit. Z1 was the only other iffy one, but I left it in). Anyways, I’ll run it thru a few band practices and see how it holds up. I did get the starter chip quick set. Still had problems pulling components cleanly (what temperature do most people use on the soldering iron?). Anyways, as an amateur hacker I’m pretty happy to fix my favorite amp.