Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: p2pAmps on July 13, 2016, 07:32:53 am
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Hey Team,
So I had a 67 Princeton Reverb come in the shop that has a host of issues I am working through. One thing however I am looking at is the PT. The one that is in this amp doesn't look like any other I have seen in a PR of this age and I have worked on quite a few. The amp is a 67 and the PT dates to 67 too but... Look at the extra wiring. There is a green/black, black, yellow/black, and red/black. Now the yellow/bk and red/bk were both tied to the fuse assembly. The other pair to the power switch. The whole thing seems very odd to me and I am very suspicious this PT is not correct for this amp.
Can you tranny experts clue me in perhaps?
Cheers,
Mike
(http://static1.squarespace.com/static/56fbe87462cd94ff6ec9d02c/5786341bff7c502ee8585a9b/5786341bd1758ebdc286f7e7/1468412957306/IMG_6793.JPG?format=1500w)
(http://static1.squarespace.com/static/56fbe87462cd94ff6ec9d02c/5786341bff7c502ee8585a9b/5786341b29687ff48a80f344/1468412957496/IMG_6792.JPG?format=1000w)
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I cannot see the part number fro the pooh glare. Maybe Export version and the 2 wires with stripes make the primary connection for 117V.
Did you measure voltages and check the striped wires for AC?
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I cannot see the part number fro the pooh glare. Maybe Export version and the 2 wires with stripes make the primary connection for 117V.
Did you measure voltages and check the striped wires for AC?
Hi Ed,
I have measured anything yet and I did wonder about export version. I have just never seen one from a old BF before.
Number are:
EIA-606-729 (1967/29th week)
CSA 827
L010020
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10020 = dual voltage for an Import/Export PT and of course you know 606 is Woodward Schumacher..
look at the AB1270 schematic and you'll see this PT
http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270_schem.pdf (http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270_schem.pdf)
maybe it is a 1977 PT installed in a BF PR...
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10020 = dual voltage for an Import/Export PT and of course you know 606 is Woodward Schumacher..
look at the AB1270 schematic and you'll see this PT
http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270_schem.pdf (http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270_schem.pdf)
maybe it is a 1977 PT installed in a BF PR...
Good info... That schematic is a little blurring for my old eyes LOL
1977? Maybe
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From Rick @ Classic Tone
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Looks like it’s a later model transformer…
Looks to me like it’s the dual primary 010020 alternate export transformer…
That one shows up in the B1270 schematic…
Date code shows 29th week of 7… maybe 1977… not 1967
Kinda tough to sort out, because there are no scars around the bolt holes like it’s been moved…
At any rate, dual primary
Rick Gessner
Tech Support - Amp Parts Direct
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That schematic is a little blurring for my old eyes LOL
this schematic is a little better it's out there for upload somehere... but I can't remember where..
(http://fenderguru.com/wp-content/uploads/2010/04/PR_NBF.png)
and also http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270.gif (http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270.gif)
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That schematic is a little blurring for my old eyes LOL
this schematic is a little better it's out there for upload somehere... but I can't remember where..
(http://fenderguru.com/wp-content/uploads/2010/04/PR_NBF.png)
and also http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270.gif (http://el34world.com/charts/Schematics/files/fender/Fender_princetonreverb_b1270.gif)
Thanks alot, that is a nice clear picture...
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I also agree it's an export transformer. However, I think it's a '67 part, not a '77 part.
I used to own a '67 Princeton Reverb with an export transformer, and it had the extra wires (which were cloth covered). I did not have the foresight to take down the transformer codes at the time. However, I'm almost 100% sure it was bone-stock when I got it. I do recall seeing the "CSA" stamp on my export PT.
I wonder if a 1977 PT would have had plastic-insulated wiring (I now the late-60's/early-70's ones were still cloth).
Fender likely had some portion of their products built with export transformers by at least the mid-60's. Yes, you didn't see many UK bands playing Fender, but as an import it would have been much more expensive than domestically-produced amps (and still is; the prices on U.S. guitars/amps is very high in the UK).
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It could be a stock '67 HPB and since it looks like it hasn't been taken out that is another clue. I would have to dig into the closet to get to my '78 to see what the PT leads were made of.
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Well one thing is for sure, this PT is bad. It has shorts in it which is probably why I found a 30A fuse in this amp! Unbelievable huh, not the first time :)
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My 73 Super Reverb does not have cloth covered wires. Not sure when they changed, but they were cloth in 69.
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Well one thing is for sure, this PT is bad. It has shorts in it which is probably why I found a 30A fuse in this amp! Unbelievable huh, not the first time :)
Well that's the problem right there, everybody should know you can't use a 30A fuse in a '67 Princeton Reverb, you have to use a 50A fuse. :l2:
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you have to use a 50A fuse.
When I graduated my final school in the Navy, the E9 that ran the school gave us each a well machined steel slug the exact dimensions of a standard line fuse, He suggested we use it sparingly :icon_biggrin:
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you have to use a 50A fuse.
When I graduated my final school in the Navy, the E9 that ran the school gave us each a well machined steel slug the exact dimensions of a standard line fuse, He suggested we use it sparingly :icon_biggrin:
Yes, sparingly. :laugh:
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Over my 38yr career, I used it 3 times, worked as designed :icon_biggrin:
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A .22 bullet works just fine too. Read about it on Darwin Awards. :icon_biggrin:
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I've been nominated more than once :icon_biggrin: