Replacing transformers

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Mollusk

Replacing transformers

Post by Mollusk »

OK, i've got a Traynor YBA-1 Bassmaster here, essentially a Marshall clone from 71. It blows fuses. I have reason to believe that it is a transformer. Antique Electronics supply has a replacement output tranny for Marshall. Will this work? As for the power tranny, i have no idea how to diagnose this kind of thing, so if it's that i need to take it in.
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Professor
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Post by Professor »

not to dispute your theory but traynors transformers are built like black boxes ive never heard of one having a problem.
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SteveinTempe
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Post by SteveinTempe »

Most likely power supply related caps shorted
output or power transformer?
If power tranny that is smoked it would blow fuses
Some times the tubes will short
try power up with no power tubes...
It may not be a transformer ?
Anyone else have Ideas?

Steve :wink:
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Plexi
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Post by Plexi »

I can attest for them going bad..alot of times its the user that usually does something to cause one to go bad etc.. but i've changed a few of these..still got an ot here that is bad,just haven't thrown it out yet..

You are right,you may not see as many,but about any transformer can go bad. But i do quite a bit of repairs,and may see alot more amps.
But it happens.

Richie
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Plexi
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Post by Plexi »

What Steven said.. pull the power tubes first.. try a new fuse.. try to power it up without the power tubes in it.. if it don't blow..most likely its just a bad tube.. you could put one in at a time..and when it blows,know which one is bad..lol

If it blows with the tubes out..you can have a shorted rectifier, or a shorted filter cap.. bad OT or PT.. Usually try the simple things first..then disconnect sections to see where its causeing the amp to blow fuses..

The bad thing is for people who don't know, they may think they just have a bad tube..which they may..but when a tube goes bad,sometimes it can leave an arc..burnt spot on the socket. If you don't clean or replace the socket.. any new tube you try to use will short out in the socket.

So its harder to just say its a bad tube,they can be other things bad or went when the tube ,OT,and other parts etc..

I guess its easy,if you've done alot of amps.. believe it or not, its usually easy to find out which section is causeing it. RG also has an amp debug page that is very helpful..
http://www.geofex.com/ampdbug/ampdebug.htm

One thing about it.. its one of the easy amps to work on!

Richie
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Mollusk

Post by Mollusk »

Yeah, these Traynors have a reputation for being rock solid. These tranny's are rust free, although i don't know beans about what actually happens to a transformer to cause it to go.
Now, if it is the OT, what problems would that cause? Problems with getting the sound out to the speakers?

The caps eh? yeah these are some ooold filter caps. From the date code it looks like they are Mallory caps from 71!!

I'm gonna go out and get some fuses, try and run it w/o tubes. Good idea. Thanks a lot guys.
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Professor
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Post by Professor »

Plexi wrote:I can attest for them going bad..alot of times its the user that usually does something to cause one to go bad etc.. but i've changed a few of these..
Richie
you're right anything is destructable but i just thought from his post that he probably hadn't modified anything.

and im sure you have seen a ton more than me. ive only ever played mine and three others.

but i cant say ive ever seen one on ebay w/bad transformers.

:)
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Plexi
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Post by Plexi »

Theres different ways they go bad.. sometimes a short.. other times they will probably sound a little weak, or maybe even when turned down they will sound ok..but when cranked will distort badly..not a good distortion.. and lose power.. and sound pretty nasty. Hard to describe in words..
but they go bad in many ways that can be different...

Mostly its due to people that have had a problem.. and put in a wrong fuse rating.. and just damaged things from misuse..lol it happens alot.

The one that i have here that is bad..came from a YSR..

Don't get me wrong, i ain't knocking them at all.. I own 2 myself..
And early one with the choke and no bumpers..and 72.. YBA1

Both sound great!! I do like the OEI OT installed over the hammond.
And more pics of taps to use.

Richie
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Professor
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Post by Professor »

i have a 69 ysr-1 and have never had a problem with it but do you think the oei transformer makes it sound more marshall like?

not that i dislike the way it sounds now but just like anything else it could always be better.

at the same time i dont want it to sound just like a marshall but mabey a little more marshall and a little less fender.
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Plexi
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Post by Plexi »

I guess its ones opinion.. But i like the OEI alot more than the hammond.

But then again, i do go for the marshall type sound/tone,and have changed mine a bit.. As you see they get bought up quick anymore, and prices have gone up. now that every one knows you can plexify them.

but the YSR is a bit different in the circut..and even the YBAs have to have some changes to plexi-fy them. I think the OEIs are more for the EL34s.. But there are many options.. heyboer makes any of the fender trannys..and a good price too. I've had a few fenders in here recently that were just fried.. gave them the number and they made them..

Richie
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Mollusk

Post by Mollusk »

Well i ran the thing yesterday, first with no tubes. Let it sit for about 15 minutes. Then i put the tubes in and waited another 15. No problems. I finally played it for a good half hour, and it sounded fantastic! It's more sensitive than my Marshall! The only thing i need to do now is take it to get grounded. :D

As to why the fuse blew in the first place... i think now that it may have been differences in the house currents. I had been using it at a friends house the times that it blew, without a surge protector. Maybe his house wiring is putting out a little more juice than mine. I have an old house, i think it might only put out 110v.
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Professor
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Post by Professor »

Plexi wrote: I think the OEIs are more for the EL34s..
Richie
my YSR-1 has el-34's. :?
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Plexi
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Post by Plexi »

Another small thing that can happen..you see this in marshall amps alot..use a slo blo fuse of the right value..
Sometimes people correct rated fuse.. but its a fast blow..

Tube amps need a slo blo.. and if its the older PT.. and 110,155,117, rated.. the extra voltage from the wall we have now days can cause a fuse to blow when you first turn on an amp.. or flip it off standby..

Just another thing to look at..


Richie
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