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Post by Carceri on Jun 25, 2007 18:29:53 GMT
I have been away for a while, so I haven't had a chance to listen to my modded X-CAN V3, but yesterday I wanted to use it again, so I plugged it in, and to my surprise... no sound. I'll spare you my trounbleshooting adventures and just describe the symptoms I experience. If I turn it on with the headphones plugged in and the music playing, after the unit warms up for a few seconds I get sound in both channels. After about a second it disappears from the right channel and a second later it disappears from the left channel as well. Everything is not dead quiet. If I turn it off at this point, after about 5 seconds I hear the music (very quiet but it's there) in both channels for about 1-2 seconds, and then it disappears again. If I turn the unit back on BEFORE I hear the faint music after turning it off (that is if I turn it off and on again within 5 seconds or so) I do not get any sound as when I turn it on after it has been left off for more than 5 seconds. When the unit is turned on the tubes are glowing and the blue LED is on. I have checked the PCB and the components, but there are no apparent damage. Visually everything looks just as it should. I have even tried changing the tubes, but that made no difference. I am really confused, so I hope some of you guys have an idea what is going on... and more importantly: How to fix it  Thanks |
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Deleted
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Post by Deleted on Jun 25, 2007 22:47:37 GMT
carceri
Are you able to check the main HT voltage supply with a multimeter/DVM ? Without a schematic, I am only guessing. Mike will be able to assist further , when he is up to speed.
SandyK
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Post by PinkFloyd on Jun 26, 2007 9:17:00 GMT
Have you just modded it and if so with what? Did this happen immediately after you modded it or was it fine for a while?
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Post by Carceri on Jun 26, 2007 11:49:56 GMT
sandyk: Yes, I can measure that if you tell me where to measure
PinkFloyd: No I modded it a little over a year ago and it was working perfectly. Then I didn't use it for about one month, and now it has the problems mentioned in my post. It has been moved around a bit during that month it was not used, but that's it.
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Post by Deleted on Jun 26, 2007 12:34:14 GMT
carceri
Better ask THE man, that one! If I had one in front of me I would know what to look at, but
Mike is the guru of the glowing bottles. (and Veroboard construction)
BTW, do the filaments stay at the same brilliance after the sound dies ? I wonder if you have disturbed a dry joint, or have a faulty connection somewhere ?
SandyK
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Post by Carceri on Jun 26, 2007 12:53:36 GMT
Yes, there is no change in brilliance after the sound dies.
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Post by PinkFloyd on Jun 26, 2007 20:19:33 GMT
Oh god I hate this type of question  For starters, you have tried a second pair of headphones with it or have tried the headphones in another amp / receiver? You have also tried another set of interconnects........ Right, now that you've eliminated the headphones / cable it must be the amp. First we will try the hot finger test..... remove PCB from enclosure, power the amp up and leave it on for 20 minutes.... touch each of the TIP110 / TIP115 transistors, are they warm / hot to the touch? If one or more is cold then replace.... I had an amp with a similar problem a short while back and it was 2 of the transistors that had gone. Are you using the 6N1P-EB? Try the hot finger transistor test first and report back. To save time you could double, triple and quadruple your solder joints and maybe even reflow a small touch of solder into each one..... you say the amp has been moving around a lot? Possible it was jolted and a bad joint has become loose somewhere...... try the obvious before looking elsewhere  |
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Post by Carceri on Jun 26, 2007 21:49:26 GMT
I just tried the hot finger test... The TIP115's are warm, but the TIP110's are just as cold as before I powered the amp on. That might be a problem...
I'm using the 6H23N-EB
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Post by PinkFloyd on Jun 26, 2007 22:25:20 GMT
I just tried the hot finger test... The TIP115's are warm, but the TIP110's are just as cold as before I powered the amp on. That might be a problem... I'm using the 6H23N-EB Change 'em then...... (The TIP110) they're as cheap as chips. best way of doing it is to undo the nut and bolt, snip the TIP110 off flush with the board and suck the shrapnel up with a desolder pump..... don't try to desolder the entire TIP110 as it will act as a heat shunt and you'll end up lifting a pad (or three) To confirm...... remove the nut and bolt, snip all three legs off flush with the board.... turn the board over and desolder (using an iron and a pump) the three pads. Insert new TIP110 and pray Should be fine  |
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Post by PinkFloyd on Jun 26, 2007 22:42:24 GMT
I know I am not an expert but before the amp is blamed, how about the psu? I bet you a pork pie it's the TIP110 miguel..... obviously I'm "guessing" not having ever seen this particular amp but it's an informed guess.... it could be one of a hundred things but the symptoms point to the transistors I think. By the way....... 80% if the innards of a v3 are part of the PSU. If this were a v2 I'd swap out the ZX653 / 753 and 99% of the time I'd be right. I'm 70% certain, given the symptoms, the TIP110 is the culprit here..... don't ask why, just a hunch ;D OP...... when you've fitted new TIP110 try her firstly with a different pair of valves. Before you fit the TIP110 I'd definitely go over all the solder joints and flood them with a small amount of fresh solder (hot iron, hold on pad until it becomes liquid and feed in 1mm of fresh solder) Maybe I'm overlooking the obvious here but, if so, it will have to be so... I have a 100% track record when something is in front of my nose but online diagnosis is pure guesswork and usually results in too many cooks spoiling the broth. |
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Post by Carceri on Jun 27, 2007 6:30:23 GMT
I will try that. Yes, I know online diagnosis can be very difficult, but thanks for trying anyway  |
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Sol
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loves motorcycles !
Chief Technical Numpty
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Post by Sol on Jun 27, 2007 7:21:59 GMT
Some excellent tips there Mike .. especially the "hot finger test".
Mine's pear-shaped again ... I'll do the finger test!
The amp was referring to was mine I assume .... the 61NPs seemed to have been the issue ... but then again maybe not!
BTW
Mental note: Don't try any more Mullards bought cheaply on ebay! They seem to feck up the amp!
Does anyone have a set of Mullards they might like to sell? Not tried them ... or rather, I've tried 2 sets - both have resulted in a dead amp - roll them in .. nothing. Swop back ... nothing also!
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Post by PinkFloyd on Jun 27, 2007 7:25:07 GMT
eh?  |
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Sol
100+
loves motorcycles !
Chief Technical Numpty
Posts: 135
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Post by Sol on Jun 27, 2007 11:32:21 GMT
eh? Memory like a sieve you! I rolled in some mullards, and it died! |
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Post by PinkFloyd on Jun 27, 2007 14:30:40 GMT
eh? Memory like a sieve you! I rolled in some mullards, and it died! You're saying it's gone "again" or are you referring to the last time? |
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Sol
100+
loves motorcycles !
Chief Technical Numpty
Posts: 135
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Post by Sol on Jun 27, 2007 19:30:44 GMT
It has gone again .. [fx: Python] it is no more .. it is currently an ex-V3
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For starters, you have tried a second pair of headphones with it or have tried the headphones in another amp / receiver? You have also tried another set of interconnects........
