Fender '68 Custom Deluxe Power Transformer Swap

[TomCarlos]

Hello Forum Members...

A friend of mine is rushing to buy a Fender '68 Custom Deluxe Amp.   He saw an ad for the amp - $500.  According to him, it looks brand new.  However, this is most likely an Export model as he said the photos appear to show Asian markings.  Given that, I believe the amp has the part 041317 Power Transformer.  I tried finding specs for this PT but could not find anything - at least anything that would tell me is has taps to work on 120v.  If you look at the schematic, it shows a Domestic PT part number 041316.  So I am believing that amps made for the US market had a different PT compared to foreign markets.

So assuming the only difference in PTs is the windings, it shouldn't be hard to drop in a Hammond 290CX tranny and simply match up where wires were connected?

https://www.hammfg.com/part/290CX

And before engaging the amp with tubes, of course I would check voltages.

Anything else to be concerned with?

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Thanks!!

Tom

[g1]

It looks to me like you could use the export transformer with a modified version of the 100V arrangement, but I will have to look further at it later (and should probably get a second opinion).

[TomCarlos]

Thanks G1 -

My friend made the drive to buy this amp.  He sent me a photo of the PT - see below.  I am thinking this amp came from Japan.  And if that is true, it most likely used the 100v tap.

I cannot find specs for A-7719527000 or E67406 SB4

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[g1]

The A-* number on the xfrmr is different than the one TAD lists for the  041317 fender part #.
Could be there was a supplier change at some point in production, or it could be this unit does not match what is shown in the schematic.  There is a Taiwan version mentioned as 110V, which is not an option shown on the schematic, so this could possibly be specific for that but I really doubt it.

For starters, I would caution against using it as is.  If it is wired for either 100 or 110V and 120V is applied, all components will be stressed, especially the main electrolytic filter caps.  Japanese AC plug I believe will fit in North American wall sockets, so it may be being used as is.

If you can check the unit and post some pictures, the areas to look at are:
a) whether the transformer wire color codes match with what is shown for the export version wiring
b) whether the CP lugs are all as shown on the schem., and how it is currently connected to them.

If it all matches up to what is shown for the export transformer, it should be fairly easy to re-wire for 120V operation.

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[TomCarlos]

For starters, I would caution against using it as is.  If it is wired for either 100 or 110V and 120V is applied, all components will be stressed, especially the main electrolytic filter caps.  Japanese AC plug I believe will fit in North American wall sockets, so it may be being used as is.

.

Thanks as always G1. 

You and I know the Japanese AC plug looks very much like the U.S. plug.  In fact, it probably fits snugly in our outlets.  So unless someone paid close attention to an amp (and knowing better), they could plug the amp in and give it a try.  Bad idea.

Even if using a variac and trying to dial in a lower voltage, I would not recommend doing this to an amp where we have no history or how it was used in a foreign market.  I would first need to verify all the components in the amp vs a schematic for domestic use - big job.

I have yet to see this amp for myself.  The more research I have done, the more I would hesitate to do a PT conversion and think it's that easy.  There are lots of YouTube vids were guys are converting USA amps to 240 for use in Australia, and they make it look real simple.  But I would hesitate to believe that.

In any event, I will do some more research only because I am curious.  For me personally, I would use great caution when buying anything used, especially an export model. Who knows what other differences can exist (that are not shown on a schematic as you mentioned).  And if not working, I would have to get it dirt cheap so that if it all went up in flames, I wouldn't feel too bad.

I always appreciate your thoughtful replies. The learning process never ends.

Tom