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Line 6, Spider 4 15, DSP little amp, 2011

Reported as problem with guitar input socket, owner tested with 2 leads and 2 guitars, and amp problem. But of course no problem with me, as received and now with the thing dismantled , including the Tx , to reconfigure under power and rattle and bend . Yes PbF, but i/p socket solder points look ok under x30, and trying to force signal contact pin out of the pcb with circlip pliers acting between pcb and protruding lump at axial end of the socket, just flexes the pcb. Anything other than wiring in a replacement conventional socket and bypassing a tiny via, in the signal line, and crossing-fingers against a bounce? Plenty of tip contact clearance in open position. The phosphor-bronze pcb grounding contacts do not constitute a ground line through the amp casing.

Reply to
N_Cook
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This amp seems to use a control line from the static ground contact of the input socket, via a couple of 4.7K and 5V to pin 90 of the 100 pin DSP chip. So normal operation is non-grounded of this static contact, hence dummy plug required , at the guitar input, to use the external signal input. I cannot see how that line could go LOW in guitar use and inhibit the amp.

Reply to
N_Cook

There may be a generic problem with these amps. I dug out a scapped board of one of these amps. That had the opposite problem, never managed to get that amp working. When I looked at it again, the static sleeve contact was tied to ground, with a dummy plug in place. Scraped around the insulating ring of ground plane around that pad and the grounding disappeared. Without a schematic, that is what you mould normally expect, the static sleeve contact being at ground. This insulating ring space is normal dimension, unlikely to induce a tin-whisker, what was bridging it.? This one , that I cannot make fail, I've messed about so much that I would have destroyed any bridge. Any ideas what was going on in the way of a shorting bridge?

Reply to
N_Cook

Is 100 +/-20 micron bridgeable by a tin-whisker? This minimum insulation gap (under x30 visibly compared with a .08mm diameter wire) is between the pad for that control pin and one of 4 grounded pads for a screening can, not used in this amp, but was used on the scrapped amp. The remainder of the ring insulation is about .3 mm. Could a flux or flux remover associated with PbF induce a whisker over 100 micron ?

Reply to
N_Cook

Next time I come across on of these, I'll make a x30 inspection of this guard band to see if I can spot any whiskers growing across, maybe under the lacquer. Just a mess of powder on both these boards now, ex lacquer, down to pcb polyester. Tried out the old board and still dead.

Reply to
N_Cook

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