Need help with 50 Watt build!!!!!

jctaudiodesigns · Post by **jctaudiodesigns** » Sat Nov 24, 2007 11:57 pm

Hi everyone, I need help. I just finished my 50 watt build and I started to test it. All the voltages seemed ok until I got to the positive terminal on the bridge rectifier, it was only 315 volts. I then read a thread about someone else who had just finished a build and he found the same thing, but he said that when he took it off standby, the voltage was right. I did the same thing and it looked good, but then it started popping. I did not see any arcs and both fuses are good.

Any ideas about what is going on?

jctaudiodesigns · Post by **jctaudiodesigns** » Sun Nov 25, 2007 12:01 am

By the way step 1 has no tubes installed.

mwm523 · Post by **mwm523** » Sun Nov 25, 2007 12:11 am

Can you post some pics?

jctaudiodesigns · Post by **jctaudiodesigns** » Sun Nov 25, 2007 12:30 am

Here are some pictures.

jctaudiodesigns · Post by **jctaudiodesigns** » Sun Nov 25, 2007 1:47 am

I just lifted the board to see if I could find a place were its arcing, I didn't. By the way, its just not 1 or 2, its a continuous popping sound. It also takes a couple of seconds after I switch standby on before it starts happening.

neikeel · Post by **neikeel** » Sun Nov 25, 2007 10:58 am

At first inspection I cannot see any specific errors (pauses and waits for SDM or Flames to pipe up....)

One general point,l ooking at your high resolution pictures (and therefore very unforgiving of soldering technique

) before you go any further I would go over all of my solder joints carefully, ensuring that the solder flows properly and all of the joints are adequately filled with solder.

When you have done that post a larger overall picyure of your board.

Good luck.

jctaudiodesigns · Post by **jctaudiodesigns** » Sun Nov 25, 2007 11:36 am

I will go ahead and get more pictures up, but I don't think its my soldering joints. I went ahead and touched up 1 or 2 that were not completely filled in , and it did the same thing. My digital cameras battery is charging but I will get the pictures up ASAP.

I have double checked every wire and component and they all seem to be in the right place and the right value. I think I might have some component failing but I don't know how to trouble shoot it.

bluze81 · Post by **bluze81** » Sun Nov 25, 2007 12:46 pm

swap out preamp tubes One at a time, I recently had a pre tube do the same thing,hope this helps, bluze

bartak · Post by **bartak** » Sun Nov 25, 2007 1:00 pm

make sure that none of the connections to the tube sockets are touching. I had two connections dangerously close on one of my preamp sockets because I bent the wire around the side of the post. It wasn't touching but it was close enough that it may have caused an arc if I hadn't have caught it in my final inspection.

jctaudiodesigns · Post by **jctaudiodesigns** » Sun Nov 25, 2007 1:39 pm

First off thanks to everyone for the help!

Bluze81, this is test #1 and I am just checking voltages with no tubes installed.

I checked the tube sockets and they all look fine.

jctaudiodesigns · Post by **jctaudiodesigns** » Sun Nov 25, 2007 2:57 pm

I have just re-soldered every one of my connections, and triple checked the board leads, everything seems right. I can't quite tell were the sound is coming from. I thing it might be coming from either the PT or the filter caps, but really unsure about it all as I don't leave it on after it starts happening.

bluze81 · Post by **bluze81** » Sun Nov 25, 2007 7:05 pm

jctaudiodesigns wrote:First off thanks to everyone for the help!

Bluze81, this is test #1 and I am just checking voltages with no tubes installed.

I checked the tube sockets and they all look fine.

Got ya , I thought you had tubes in it, sorry, please list your voltages you come up with, alot of guys on the forum can help track down the problem,it seems someone recently wired the rectifier block wrong on one the new kits,you have double and triple checked all your wire layout? good luck with it hope its an easy fix. bluze

jctaudiodesigns · Post by **jctaudiodesigns** » Sun Nov 25, 2007 11:04 pm

My voltages all look good with standby off, but when I flip the switch, I get that popping noise, and it does not sound healthy, so I can't get past that step.

bartak · Post by **bartak** » Sun Nov 25, 2007 11:46 pm

I feel for you man, I had some problems and it sucks. one possibility is when you heat up the turret from the top the wire can fall out of the bottom or become loose. you can check for continuity between the turret and the corresponding wire. I did this just for good measure. also turn it upside down and shake it. I did that and all kinds of little shit came out. If its popping it's more likely that something is wired wrong or shorting out. I went over mine three times before I plugged it in. I got a highlighter and traced every wire and highlighted it on the layout as I went along then did the same for the circuit board. good luck

bluze81 · Post by **bluze81** » Mon Nov 26, 2007 12:03 am

What value is the resistor in front of the diode bias section? should be a 220k I beleive, its hard to tell from the picture.