Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: saturated on September 05, 2023, 01:30:30 PM

Title: transformer test 5 Sept 2023
Post by: saturated on September 05, 2023, 01:30:30 PM
fortunately this didnt have more than three wires on the secondary side

green to green

IMG_20230905_120943764.jpg

then each green to yellow/green

IMG_20230905_120958976.jpg

IMG_20230905_121020433.jpg


 that last pic looks a little too close for comfort
 :(

I presume that yellow/green is the center tap.... :P

time to read about center tap(s)

the two green went to a bridge rectifier

the yellow green went to an 8 pin chip...and back to the primary fuse holder.... :o


hope you had a nice labor day weekend

 :)
Title: Re: transformer test 5 Sept 2023
Post by: Tassieviking on September 06, 2023, 12:44:03 AM
That would be the perfect setup for a 20-22v dc supply with -+ rails, usually the center tap is connected to ground as it becomes the 0v for the supply.
What did it come out off ?
Do you have a schematic of what it came out off ?
Title: Re: transformer test 5 Sept 2023
Post by: saturated on September 06, 2023, 11:47:55 AM
thank you sir

it is from a metronome i brought home from my friends junk store

IMG_20230902_150400277.jpg

it had a blown fuse

IMG_20230902_143844681.jpg

when i replaced the fuse and powered on dbt it made a horrible louder than heck noise so it was instantaneously disconnected
and the bulb was burning BRIGHT

on my to do list : mount switch on my dbt!!!  :o

I suspected the bridge rectifier but when removed it tested good out of circuit

IMG_20230902_213125123.jpg


so it has a short somewhere and there is no schematic

also there is a TO-3 ? that is $$$$$$$$  it may be good idk

I was hoping to fix it without bothering you guys ha ha (YEAH RIGHT  :)  )

but i really like it

would be cool to use it playing guitar

\m/
Title: Re: transformer test 5 Sept 2023
Post by: g1 on September 06, 2023, 02:19:59 PM
Quote from: saturated on September 05, 2023, 01:30:30 PMthe yellow green went to an 8 pin chip...and back to the primary fuse holder.... :o
If this is true, do not operate the unit.  The secondary and primary sides of transformer should never be connected.
The AC cord white and black should go to the primary (through the fuse and the power switch), and nowhere else.

If that fuse is on the primary side, the fuse holder should not connect to anything on the board.

It's worth a try to contact the company, you never know if they will supply schematic until you ask.
https://www.mcadamsinstruments.com/contact
Title: Re: transformer test 5 Sept 2023
Post by: saturated on September 06, 2023, 06:52:38 PM
thank you sir

sorry for the false alarm

I went and looked and the trace simply runs beneath the plastic fuse holder

IMG_20230906_174332688.jpg

it seems to run to a jumper connected to an input jack which snapped when i looked at it

IMG_20230906_174347008.jpg

my apologies