Bugera 1990 help

[dodgercrazy]

hello all, nOob here

I bought a bugera 1990. I asked bugera if it would take el34 tubes and they said yes. I installed them and when i turned the amp on to bias it i noticed the was no reading on my multimer. I was using eurotubes bias probe. I then noticed the tubes were not glowing or warming up at all. I removed them and reinstalled the stock 5881's, with the same result. Any suggestions for things i can look for? I am new to amps, but am not new with working around high voltages since i work at a power plant. I understand the schematics cannot be handed out, but if there are some pointers from you all as to where to look that would be great. Thanks!

[SWEINC]

If this amp is like the other Bugeras I have seen then if you follow the leads from the power transformer for the tube filament voltage to where they connect to the circuit board there will be a connector on the end of the transformer leads that plugs into the PC board. Look at it carefully and you will most likely see it is burnt inside and no longer connecting the wires to the PC board. Cut the connector off and solder the wires right to the header on the board and you should have no further problem. This was caused by the connector not making good contact. The filaments draw a lot of current especially when cold and the current arcs across the poor connection eventually causing it to disconnect and fail.

[dodgercrazy]

well come to find out, bugera 1990 will not work with the el34's. So now i need to figure out how its going to get fixed, im assuming I may have to send it back to bugera since someone from bugera was the one who told me it would work in the first place

[Jazz P Bass]

There are a number of issues at play when swapping 6L6 to an EL34 tube type.
The EL 34 draws 1.6 amps of heater current.
The 6L6 draws 0.9 amps.
Bugera used the absolutely cheapest heater connector.
Instead of wrapping around the connector pin, the female pin has one contact side.
The heater current melts the connector.
Open the amp & look at the connector.
If it is discolored, the EL34's took it out.
As the above post states, the "fix" is to wire the heater conductors direct to the board.

[txstrat]

well come to find out, bugera 1990 will not work with the el34's. So now i need to figure out how its going to get fixed, im assuming I may have to send it back to bugera since someone from bugera was the one who told me it would work in the first place

If you're still in warranty and have the name of the one from Bugera who told you, why not try.
I doubt a little they will take on it. They might say you should have given the amp to a qualified tech.
If they don't take on your warranty I'd go with Jazz P Bass's advice.

[Enzo]

Just put the old tubes back in it, no one will know you had the EL34s in there.

EL34s draw more heater current, but not so much as to pop the fuse right away. And certainly not enough to burn up a connector instantly.

Besides, if this amp is remotely recent, they have already eliminated the connector that was failing.

Chances are real good you have a blown fuse inside the amp.

[Prairie Dawg]

+1. Look for a bad fuse or some interruption in the filament supply if they're not lighting up.

[dodgercrazy]

Thank you all for the info.
Ill go through and check the fuses tonight. The amp is only a month old, so i would think its one that has had the connector issue resolved. I got in touch with the bugera service rep, but i didnt give him all my info so if i cant figure it out i may just put the original tubes in and send it back as was suggested.

[dodgercrazy]

It may sound kind of flimsy, but i went to the youtube channel ran by bugera and whoever runs the channel was the one who told me they would work. I took a snapshot of the post in case they delete it

[dodgercrazy]

well i found my blown fuse, its labeled F2, not sure which one that is for but now i just have to go get a new fuse and try it out