Help Indentifying OT

[GregS]

The OT in a blackface Fender Bandmaster AB763 amp I just got has the codes 022848 606-6-04 engraved in it. These are the only codes I can find. Initially I thought it was not the original for the following reasons:

1. The schematic I have lists a part number of 125A6A for the OT.
2. It has a 2 hole mounting pattern and was installed in a shoddy fashion with self tapping screws (inconsistent with how the other transformers are installed).
3. There is a four hole pattern in the chassis which I assumed was from the original OT.

However I was looking at other Bandmaster schematics and they had the code 022848 listed beside the part number 125A6A. So now I'm not sure if it's the original or not. If it is not the original would anyone know what the impedance of the secondary is for this transformer?

Thanks,

Greg

[52 Bill]

The 022848 number is the CBS part number, added after the takeover from Fender. The 606-6-04 is the Schumacher date code.

The parts are the same specs, with an output impedance of 4 ohms.

As far as I remember the Bandmaster outputs were always mounted with 2 screws. Were the 4 holes in the chassis used earlier or are they just punched into the chassis?

As for originality, what are the codes on the other transformers?

[GregS]

Thanks for the reply.

Were the Bandmaster OT's typically mounted with self tapping metal screws like this one? The 4 holes in the chassis appear to have never been used. I also noticed another unused hole under the choke. These holes are definitely part of the original chassis due to their accuracy and neatness - they were not drilled by hand. Was the Bandmaster built on a generic chassis that was shared with other Fender amp models?

The codes on the power transformer are 125P7D 606-604. The codes on the choke are 125C1A 606-5-47.

Greg

[52 Bill]

Yes, the transformer should be mounted with philips head self tapping screws, just like the ones that mount the choke.

Fender used the same chassis for a number of models. That's why there are unused punched holes in the chassis. Other amps would use different transformers, etc.

Your other transformers date to the same time period as your output, so I would believe that they all are original to the amp.

If you didn't know this already, the transformers are EIA date and manufacturer coded, when they were made. The most common supplier to Fender for transformers was Schumacher. The code for Schumacher is 606. The manufacturer code is followed by a date code with the year followed by the week of the year.

So your power transformer marked 606-604 was manufactured by Schumacher in 1966 during the fourth week.

Your output was also made at the same time.

Your choke was made during the 47th week of 1965

[GregS]

Ok. Thanks for the info.

Greg