18 Watt startup Problems

[JT]

I went to do a startup and check voltages and ran into some problems. The Power and rectifier tubes fire up but i barely get a reading on the switches and fuse . The power light seemed to be on when in the off position although i wired it just like it is supposed to be.Also the biggest issue is the the resistor on the Capcan started smoking when the amp is switched off of standby. if you can give me any ideas on what to check out I would appreciate it.
Thanks![/img]

[JT]

anyone? ....Beauller?........anyone?.......Beauller?

[markh]

First thing, remove all the tubes and check with a meter or contnuity tester that there's not a short to ground anywhere in the PS R/C chain.

Next fire it up (still no tubes) and check the AC voltages.

If everything still looks OK, try just the rectifier tube.

Based on the smoke, I suspect a miswired connection, a shorted PS cap (even new ones can turn up this way), or a bad EL84.

--mark

[JT]

Thanks guys!.. i will re-check everyhting and report back....I am sure i must have mis-wired something....Just wanted an opinion on what to check out ......I appreciate the fast reply ....sorry for the cheezy movie quote

[JT]

I forgot.......this is a complete Kit from Graydon...this is also my second 18 watt build buit first head version.I do have PICS but don't know how to post them...... Thanks again!

[JT]

Richie,
The layout is the same as the Head version that was posted on the Yahoo site as far as i can tell. The only differences is an IEC power socket and a tremolo switch for manual/and FTswitch...I agree on a temporary place to post pics on the site ..and maybe a quick load program like ebay uses to post PICs right from your Drive.....I will check everyhting over on Monday and i am sure the traffic as you said will pickup and i will get some more ideas.....I basically finished wiring it up and had a few minutes to do a quick startup and as soon as i saw some smoke i turned it off......The smoke appeared about 30 seconds after i switched it off of standby....Thanks for the help and i will post on Monday

[AdamK]

You can load the pics right into this thread by hitting the "attachment" button on the page you use to type in a message. For example....

The problem is that the gallery's user permissions are not that granular, it's an all or nothing kind of thing. Kinda an administrative nightmare and tough for world-writeable albums. But the next version they say...Sorry!

Adam

[Gabi]

Richie...

Adam is right on. The great thing about people beeing able to attach their troubled amp pictures in their forum message is that you have everything in one spot (thread), simptoms/pictures/solution....

This way if someone else in the future has the same problem, we'll bw able to reffer that particular thread.

Maybe after a time would be a good idea to create a separate folder wehere we can have all this common known problems (threads) called something like Known and Resolved Bugs.

Gabi.

[JT]

PICS are posted in the gallery in my folder JT's Amp in the troubleshooting folder...Here is where i am at:
i did a quick check on the wiring and everything looks good.....Richie had pointed out that he saw on V3 was miswired. I was looking at the resistor that is connected to the .05 and the 100k as a Jumper and had the wires reversed,,,i did not realize that there was a difference on which side the wires ran to since they were connected together with the resistor....I think my probelm might be in the IEC connections......I took a few measurements and while i got a 122.7 VAC on the one side of the power switch and the Lamp ..i got a very weak reading on both sides of the fuse.......i think i might have the wires wrong from the IEC.I think i have it mis-wired.....If look at the IEC and there is one lug on the Top and two on the bottom (triangle) I have the one on the top as ground and the one on the lower left as White neutral and the one on the lower right as Hot Black......While the Black gave me no real reading i measured the white and it cam in as 123.1 VAC......Did i wire this wrong? Graydon pointed out that i had the Switches upside down DOH! so i reversed them and that is fine now.Thanks in Advance for any help!

[markh]

The black should be hot, reverse the black and white on the IEC if you want to be absolutely correct. I don't think this is your problem, though. Nothing jumps out at me as obviously wrong from the pictures.

--mark

[JT]

Thanks Guys!
..........Heres where i am at. I reversed the white and black wires on the IEC socket and it seemed to bring voltages to the Fuse that were no there before. After doing this the switches reversed again .I took some measurements in standby here they are:

Fuse: 121.9
Lamp: 121.9
Power: 121.9


V1,V2,V3
4/5: 3.33
9: 3.33
V4,V5
4: 3.33
5: 3.33

V6
1: 311.5
2: 311.5
3: 286 VDC
4: 11.09
5: 6.68

It looks like there is a problem with the PT hookup maybe? I am not sure . When i take it off standby the capcan resistor starts to smoke and starts turning red . The Rectifier and Power tubes glow and look fine. I have the B+ and the OT going to the lower left of the Capcan ( i have ground on the top for orientation ) and the standby going to the lower right lug. Maybe i Should try reversing the standby wires? I Can take more PICs if that would help .Thanks again guys.....

[JT]

Another update: I double checked my V6 wiring and it looks correct. I check the cap can wiring and this is what i have :the ground of the cap is facing the tube side and grounded on the PT lug. On lower left side + lug i have the OT Red and the Standby and on the lower right side + lug i have the B+. I took all the tubes and the resistor seemed to NOT fry anymore. Any Thoughts?

[JT]

Thanks Richie!...... And thanks to Paul Ruby i might have found the problem......Seems like i miswired an on Board Cap and grounded an adjacent resistor instead to the main buss,i am going to resolder that and see what happens....thanks again .you guys rule!

[JT]

Paul,
i emailed you privately .....I have a bunch of Pics posted in the Gallery Section on this forum under JT's amp........your welcome to any of them ..i email me and i can send you PICs of anything you like..Thanks for a Killer Turret Board!