Cheddar Bob
New Member
Hi AK folks. Long time lurker, first time caller! I'm normally a vintage tube audio guy but couldn't resist a 30 buck SX-1980 at a garage sale maybe 15 years ago. It has the typical toasty power supply board with much of the foil hacked up by a PO. Back then, I couldn't find a used board to rework, so it went to the "someday" shelf.
A few months ago I stumbled on one of these slick new boards on ebay from txturbo and went for it. It looks like a great piece of work and I understand several here put in their two cents, so I hope I've come to the right place!
I now have the new board by txturbo installed and i believe the wires are where they belong. But before I try to give it a go I'd like some direction on the resistance measurements I got as it looks like some are off. I've listed just the weird ones. Wires not listed measure per the instruction sheet.
Measured resistance to chassis ground
W3 30.8k, should be 36k
W8 seems to act like charging a cap, never goes full short like instruction sheet lists
W13 56.6 ohms should be 214 per instruction sheet
W14 56.6 ohms should be 101
W22 2.0 ohms, should be 2.8
W23 2.0 ohms, should be 3.0
W20 .6 ohm should be 1.5
W19 .6 ohm should be 1.5
W24 .2 should be 1
W25 .3 should be 1
A little more info.. .
There is a chance I have a wire swapped on W13 and W14. There is one on 13 and two on 14 and they're all pink. But I don't think it matters since the board ties them together, right?
Also, I've replaced the 22,000 uf power supply caps, and replaced caps on GWH-109 and GWH-110.
If it matters, on the original Power supply board, the two 1A fuses were blown. The others were not.
I suspect there are things going on with some of the other boards but I haven't gone down that road yet. Judging from the dust on them, they appear to have never been touched.
I'd appreciate any tips or being pointed in the right direction.
Thanks! Dave
A few months ago I stumbled on one of these slick new boards on ebay from txturbo and went for it. It looks like a great piece of work and I understand several here put in their two cents, so I hope I've come to the right place!
I now have the new board by txturbo installed and i believe the wires are where they belong. But before I try to give it a go I'd like some direction on the resistance measurements I got as it looks like some are off. I've listed just the weird ones. Wires not listed measure per the instruction sheet.
Measured resistance to chassis ground
W3 30.8k, should be 36k
W8 seems to act like charging a cap, never goes full short like instruction sheet lists
W13 56.6 ohms should be 214 per instruction sheet
W14 56.6 ohms should be 101
W22 2.0 ohms, should be 2.8
W23 2.0 ohms, should be 3.0
W20 .6 ohm should be 1.5
W19 .6 ohm should be 1.5
W24 .2 should be 1
W25 .3 should be 1
A little more info.. .
There is a chance I have a wire swapped on W13 and W14. There is one on 13 and two on 14 and they're all pink. But I don't think it matters since the board ties them together, right?
Also, I've replaced the 22,000 uf power supply caps, and replaced caps on GWH-109 and GWH-110.
If it matters, on the original Power supply board, the two 1A fuses were blown. The others were not.
I suspect there are things going on with some of the other boards but I haven't gone down that road yet. Judging from the dust on them, they appear to have never been touched.
I'd appreciate any tips or being pointed in the right direction.
Thanks! Dave
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