Cut out because owner was connecting to speaker with lead connected to amp and touched the plug-tip to guitar strings. I cannot find anything wrong with it now. I downloaded , something like the schematic version here from
formatting link
series.pdf
I cannot see how any protection circuitry would work/ reset themselves in this fault mode. Anyone familiar with these amps.? I'm surprised the Cockroft Walton pump cirrcuit is enough to power the HT of the ECC83.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
As Homey says, look again. Although it's peculiarly drawn, it is just a simple full wave bridge, with 250v AC input. The caps are just spike bypassers to protect the diodes. As to why it cut out, it may be that something locked out that complex soft-start circuit. Give Trace Idiot a call and just ask. I've found them pretty helpful in the past ...
I see what you mean , either cyber-squatters or duff connection etc, ie waste of time
formatting link
formatting link
formatting link
unless you know of the correct URL or a genuine one that works with Firefox, i may try IE later. I've never got on with this new-fangled viewing schema on a monitor business, especially disjointed ones. I'll try printing off the first one but i've been there before as well. Yes the string of diodes and little caps is not a diode pump. Some strange HV stuff here, front panel "lamps" that are 3 legged phosphorescent bulbs - where would you go to get generic/ not main agent replacements ? no obvious HV wiring , a triac protection?/crowbar cct that i've not physically located yet, presumably under the rear panel or different model
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
I found the diag you refered to, I just wondered how you found it, and is there a way to navigate back from that url to an index of diagrams fro the rest of the range. I`m more interested in the small acoustic combos as they are fairly common around here.
I repair quite a few of the TE bass amps, almost always they fail because they have been shaken apart rather than electronic problems.
There`s a well blown up Bass head under my bench which was never collected by the customer after I declined to repair it. I think that`s a GP12.
As i was, it is a diode pump, ladder steps 50V, 90V, 130V,170V , under load of ECC83. I just cannot make the whole thing not work now, damned annoying.
Just downloaded the first schematic that turned up in a searchengine that was not 18Mbytes or such. I don't like the 2sJ50, 2SK135 mounting arangement. Cases electrically connected via black anodised? bolts and only one of those each, relying on the pcb not to deform under screw pressure/ thermal effects. Exposed 230/110 mains select switch asking for trouble in the UK, nothing unusual there.
If it was used as i received it then the ground lift was in operation so if the guitar was connected to this amp then not earthed via the preamp so it was probably a static discharge. I'll replace the CMOS 4011 and 4066 as presumably they are the most likely to be affected. I still don't see why as the speaker output is earthed whether ground lifted or not.
pasted into the Google search bar found a more specific model in my case, the AH 250 ink on the paper label had faded to almost illegible on the back of the amp. I agree another useless site for accessibility.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
But have you tried contacting Trace Idiot themselves ? Many of these manufacturers are a lot more helpful than you might imagine. I currently have a Traynor Custom 40 in for repair, with a standby switching problem - easy one you might think, but the output stage HT is actually switched by a FET / opto isolator arrangement (!!). I could not find the specific model on the Yorkville website, so I mailed their technical department. In less than an hour, I had a mail back from one of their engineers, with some useful suggestions, and a pdf of the service manual attached. Now that's what I call support !
Hey Ron, how's it going ? I also do a lot of Trace Idiot bass heads. Have you had a lot of trouble with the main smoothing caps hanging out of the board ? I had one just yesterday with an odd smoothing problem. The reported problem was that it "cracked up when a bass guitar was put through it, and an open E was played". On idle, it sounded fine, no hum or other nasty noises. With normal music going through it, again it sounded fine. But when
40Hz from a signal genny was put in, it sounded harsh like a ripped speaker cone. On the scope, you could see a disturbance on the waveform - but nothing *really* significant. Turned out that BOTH the smoothing caps on the negative rail to the output stage, were COMPLETELY open circuit ! A new pair sorted it. It's amazing that it didn't show more obvious symptoms to point to caps this badly defective.
I,ve seen them mechanically out of circuit due to the solder joints being fractured but so far not seen an actual faulty cap. I have seen lots of Peavey Impulse powered cabinets with internally intermittent o/c smoothers, even replacement ones have failed after a time, yet Peavey technical say they haven`t heard of the problem.
Usually the Trace Elliots come in with the graphic eq board hanging off, and the little switches broken. Bass players drive em till they stop working!
I owned a Trace 250 head. It was very reliable and I did not baby it. I sold it when I acquired a Crown Microtec 1000 amp and a BBE bass preamp back in the 90's and have been using that combo for going on 11 years. I know when I hit the Crown's on switch it's going to work but I still take an old BGW 350 missing a channel along just in case.
--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004
COOSN-266-06-25794
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.