[Rex Lannegan]

I just picked up a used DC-5 and for the 20 minutes I got to play it I really liked it. However the giant puff of smoke and the smell of burnt transformer was rather disappointing.

Anyway..I'm looking for a new power transformer. 561054 is the part number. Does anybody know where I could find a replacement in Canada?

Powertransformer for Single Rectifier Solo 50, F50, Rectoverb (230/240V), Nomad 55, DC5 and DC5B

lamination: 3 3/8" Stack: 2"

Montage auf 71mm x 79mm

Abmessungen: B x H x T: 86mm x 73mm

Secondary:
340V Red
50V Blue
0 V Green/Yellow
340V Red

3,15 V Green
0 V Green/Yellow
3,15 V Green

 

[keto]

Unlikely, I would guess. Mesa customer service supposed to be pretty good to deal with, I would call and ask them.

 

[losch79]

Mesa customer service is top notch. I have had nothing but positive experiences with them. Send them an email and they will get back to you within 24 hours.

 

[Rex Lannegan]

Thanks guys...I contacted them and they got back to me quickly. They have one but shipping and customs is crazy on it. I'm hoping I can get one through a dealer in Canada.

 

[losch79]

You could always ask to see if they'd ship it via USPS instead of UPS or FedEx both who should be avoided at all costs if getting something shipping from the US due to the absurd custom and brokerage fees. I know some people like the sounds of Mercury Transformers in there Boogies instead of the Schumacher transformers. I prefer the later... You could also see who services Boogies in your area and give them a call. I'm not sure how many options you'd have in PEI though.

 

[Scottone]

Since this is the tech board, any indication on why the power transformer self destructed after 20 minutes of play time?

 

[Rex Lannegan]

Well...when I bought it from the guy, all I could smell was pot and he was very baked so I didn't notice any smell until I got home.

Once I had it home I could smell that bad smell and popped it open to investigate and that's when I found the cooked wires to the indicator light which is fed from the 3v tap which also feeds the heaters. The guy did tell me that he replaced the power tubes.

I can't find anything else that's burnt so I'm thinking it was a tube failure or a problem with the indicator bulb which cooked the insulation on the 3v and then the neighbouring 350v and caused the short and damage to the PT.

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[greco]

WOW! Those pics look nasty!!

Hope you can find a transformer in Canada...preferably close to PEI.

 

[Scottone]

Well...when I bought it from the guy, all I could smell was pot and he was very baked so I didn't notice any smell until I got home.

Once I had it home I could smell that bad smell and popped it open to investigate and that's when I found the cooked wires to the indicator light which is fed from the 3v tap which also feeds the heaters. The guy did tell me that he replaced the power tubes.

I can't find anything else that's burnt so I'm thinking it was a tube failure or a problem with the indicator bulb which cooked the insulation on the 3v and then the neighbouring 350v and caused the short and damage to the PT.

+ QuoteReply

that sucks....hopefully you can locate a replacement for a decent price

 

[Rex Lannegan]

Thanks guys...it really does suck. I got a price from Mesa which isn't bad but shipping is brutal. Im hoping to work something out with Long and McQuade as they're always awesome to deal with here.

Looking at the circuit it seems odd that they would use the heater wire circuit to power the bulb but then again....they know a lot more about amps than I do!

 

[greco]

Not wishing to derail this thread, but could someone explain (in simple terms ..to the extent possible) how the Rhythm Boost relay circuit works.

For educational purposes only.

Thanks in advance.

 

[jb welder]

Looking at the circuit it seems odd that they would use the heater wire circuit to power the bulb but then again....they know a lot more about amps than I do!

Running the power lamp off the heater winding is fairly common. All vintage Fenders do it that way.
I hope you can get a decent price for the PT but after shipping and in Canadian dollars they end up quite expensive. Once you get a final price, compare it to what a Mercury Mag would cost after shipping.

could someone explain (in simple terms ..to the extent possible) how the Rhythm Boost relay circuit works.

Not likely a simple explanation.
Those are just the coil (activation) halves of the relays shown. There would be the switching sides (RY1 etc.) in the pre-amp circuitry where you would see what they are actually switching in/out.

 

[greco]

Not likely a simple explanation.
Those are just the coil (activation) halves of the relays shown. There would be the switching sides (RY1 etc.) in the pre-amp circuitry where you would see what they are actually switching in/out.

Thanks @jb welder . That actually helps very much as it explains that only half of the information is provided in this part of the schematic.

 

[Jerome]

Perhaps there is a suitable Hammond replacement. They have drop in replacement transformers for many Fenders. I would think there would be one very close spec wise . Good luck with your amp.

 

[Rex Lannegan]

Perhaps there is a suitable Hammond replacement. They have drop in replacement transformers for many Fenders. I would think there would be one very close spec wise . Good luck with your amp.

I was looking at this one as it has a pretty close output. The Mesa is looking for 3.15 for the heaters and this is providing 5. I'm not sure it would make that big of a difference.

http://www.hammondmfg.com/pdf/EDB290CX.pdf

 

[Jerome]

Hi Rex
The 5 volt winding is for a rectifier tube. There is a center tapped 6.3 volt winding for the preamp and power tubes. Or you could call it a 3.15-0-3.15 volt winding. That's where the 3.15 v figure comes from.

 

[Rex Lannegan]

Hi Rex
The 5 volt winding is for a rectifier tube. There is a center tapped 6.3 volt winding for the preamp and power tubes. Or you could call it a 3.15-0-3.15 volt winding. That's where the 3.15 v figure comes from.

Some people know just enough to be dangerous.

I'm looking at this guys:
https://www.hammfg.com/files/parts/pdf/290DX.pdf



I'd prefer the Mesa drop in but it's looking like $200 US shipped and then any customs on top of that. Pretty pricey compared to the Hammond which is available in Canada for more than half that price! Hammond 290DX - Power Transformer

 

[Rex Lannegan]

I'm thinking the 290DX is a match but the secondary has 650v instead of 700v. I'm not sure how much effect the 50v would have on the performance of the amp?

 

[jb welder]

Depends what you like. If you need every bit of clean headroom, you might miss that difference.
If you don't need the clean power, you might even like it better with the slightly lower voltage.
By rough calculation, you will lose about 30 to 40VDC at point A shown by the stand-by switch (and on down the line).
It's only about a 10% variation, you could almost see that kind of variance due to line voltage differences in various parts of the country.

Is it going to drop right in as far as physical mounting considerations?

 

[Jerome]

If the Hammond does not drop into the chassis cutout for the existing transformer , I would bite the bullet and get the Mesa replacement. Assuming the existing transformer mounts through the chassis.
If the Hammond drops right in , and it was my amp , I would buy the Hammond part. If it was a customer's amp , the customer would have to decide. Resale value would likely be negatively affected , and the sound of the amp might be different.
Bit of a gamble there. I don't have any experience with this exact scenario so am inclined to say go with the Mesa transformer , and too bad about your luck. Perhaps the previous owner will help defray the expense. Though good luck there.
Also should mention that you want to be certain that the fault that caused the transformer to blow has been corrected.
Replacing a power transformer is a job that should be done by an experienced technician, or if you do the work yourself , have an experienced tech check the work before you fire the amp up.