JTM45 Clone little problem!

voodoo.chile · Post by **voodoo.chile** » Fri Aug 26, 2005 4:20 am

If I remove the first preamp tube the ampli don't work (No sound).
For the second, I must try and I let you known.

For the cronicle, when I try the ampli after rewiring I must change the firstpreamp tube why hes was broken !?!

voodoo.chile · Post by **voodoo.chile** » Fri Aug 26, 2005 7:39 am

NEWS:

If I leave the V1 (first preamp tube) I have no guitar sound but HUM/HISS present.
If I leave the V2 (second preamp tube) I have no guitar sound and NO HUM/HISS!

I send us my voltage chart, we have a values with no matched the standards value.

V1 194 - 1.96 3.5 3.5 208 - 2.00 3.5
V2 168 - 1.21 3.5 3.5 345 186 197 3.5
V3 230 - 45 3.5 3.5 247 - 48 3.5

V4 - 3.5 494 494 -44 480 3.5 - N/A
V5 - 3.5 494 494 -44 480 3.5 - N/A

V6 - 493 - 393 - 393 - 493 N/A

We don't think we have a caps broken?

voodoo.chile · Post by **voodoo.chile** » Fri Aug 26, 2005 9:23 am

Another strange thing:

When I turn ON the power switch, the power trasformer start to make a little "vibration" and a "MMMMMMMM" sound.

Is Normal?

Flames1950 · Post by **Flames1950** » Sat Aug 27, 2005 12:05 am

Your voltages are higher in most cases, but overall they follow the right "pattern" so I'm not sure that's an issue. (Some PT's do like to vibrate, annoying though it may be....)
Did you have a new pic available yet? I'm curious about the two yellow wires between the board and the second preamp tube, one almost looks like it could be hooked to the wrong spot on the board but since they all connect underneath I can't be sure. (And I don't know what the symptom would be if they were hooked the way I'm wondering about, so I don't have that information to go off of either.)

Flames1950 · Post by **Flames1950** » Sun Aug 28, 2005 1:12 am

I found your old pics on my hard drive still, they look like the yellows go to the correct spot.
I had something else on my mind that I was trying to post last night when George's server was taken offline, and now I can't remember what it was dammit.............

voodoo.chile · Post by **voodoo.chile** » Mon Aug 29, 2005 7:13 am

I want post new pic of work, but I receive a message, why have reached limit of upload 2MB (?!?!?)

I think the work is right now!

But I have the same problem.

If you see the first pic of this post, you think the wires in excess from PT which I don't have cut, can make the trouble?

Can be broken the resistor on V2?

Can be broken a filter cap or a cap on board (TREBLE LINE)?

Flames1950 · Post by **Flames1950** » Mon Aug 29, 2005 3:07 pm

You could try replacing the resistor mounted on V2's socket (a 100K.)
Old Fenders make this kind of noise as the carbon composition resistors on the preamp plates get old. Usually the carbon films you've got in there aren't as bad, especially considering that they're relatively new. But we've already looked at a number of things, and replacing a resistor is cheap.........

voodoo.chile · Post by **voodoo.chile** » Tue Aug 30, 2005 3:20 am

Yes, the resistor is pretty new, but I have soldered and desoldered the wires on the pins, at least for three times; the first, the second for shortening the wires, and the last for rotate the preamps sockets.

PS: where are the symproms for a bad/broken cap?

Flames1950 · Post by **Flames1950** » Tue Aug 30, 2005 6:58 am

Every bad coupling cap I've had made the signal sound very distorted and fuzzy, unclear and a little "broken-up." I've never noticed any excess hum or hiss but it's been a few years.

voodoo.chile · Post by **voodoo.chile** » Tue Aug 30, 2005 9:10 am

I've changed the 100K resistor on V2, but no result!

I want try to change the PT wiring, tightening the HT wires to rectifier tube, and I think I have make an error on B+ fuse wiring!

Is possible?

PS: Why I can post a pic?

Post by **VelvetGeorge** » Tue Aug 30, 2005 1:13 pm

I've checked into the 2M limit on attachments and it seems to be built into the php code for the forum. Apparently there are limits built into the server as well. There is a 2M per member limit and a 100M overlimit.

I'll see what can be done about this. For now I think the easiest way to post images will be to edit old posts and remove unecessary images.
That is a crappy work around, I know. But it's all I have for right now.

If I just need to buy more server space I will.

George

voodoo.chile · Post by **voodoo.chile** » Tue Aug 30, 2005 1:45 pm

Thanks George, I try......

Any suggest for my trouble George?

Flames1950 · Post by **Flames1950** » Tue Aug 30, 2005 5:35 pm

VelvetGeorge wrote:I've checked into the 2M limit on attachments and it seems to be built into the php code for the forum. Apparently there are limits built into the server as well. There is a 2M per member limit and a 100M overlimit.

I'll see what can be done about this. For now I think the easiest way to post images will be to edit old posts and remove unecessary images.
That is a crappy work around, I know. But it's all I have for right now.

If I just need to buy more server space I will.

George

Many Internet Service Providers give you free homespace for hosting pics, etc. even if it's not obvious.
I'd really leave it up to the individual to get pics hosted, all that server space is money and it can't grow/be spent unchecked forever. You're generous to a fault, George, but you'll have to put the ol' foot down sooner or later.............
Otherwise you may want to look into limiting the size of the individual pics to 800x600 for stuff that you're hosting, so that the 2Mb is maximized. But that sucks for detail shots to help with troubleshooting.

Post by **VelvetGeorge** » Tue Aug 30, 2005 6:10 pm

I thought the limit was 800x600. I'll check again. I agree that there needs to be a limit. But it's hard to limit members with 1,000 plus posts. And if I did, how would I decide which info to keep and which to discard?

Ultimately, you will have to host your own pics. Fortunately, there are lots of free hosting sites, as you mentioned.

George

Flames1950 · Post by **Flames1950** » Tue Aug 30, 2005 11:34 pm

voodoo.chile wrote:I've changed the 100K resistor on V2, but no result!

I want try to change the PT wiring, tightening the HT wires to rectifier tube, and I think I have make an error on B+ fuse wiring!

Is possible?

PS: Why I can post a pic?

You can change the power supply wiring if you like, but it really rings of a problem introduced in the preamp and sent along from there. It's just being pretty nasty about letting us find it!!

How about the ground buss on the back of the control pots, did it go on securely? Did you scrape away the surface on the back of the pots a bit to expose fresh metal that the solder could stick to better, and really let the pot casing heat up until the solder flowed out easily? I'm assuming we've already made you recheck all those connections at the board, pots and sockets over and over already..........