Hi! Who Want's Help Install MMs In My AC15HWH?

[power chord hack]

Hello!

Power Chord Hack, here.
New to this forum but I'm sure a few here know me from other places on the interweb
For amp experience I've built an Allen Encore & BFed and fully recapped my 78 Princeton Reverb. I've also built a few pedals.

OK - So I've got an AC15HWH and want to install a MM OT and choke.
The MM color codes seem to be different from the Vox.
I've been googling this all day & came up short.
Anybody here done this?
Any insight on which wire is which?

Here's the schem:
http://www.blueguitar.org/new/schem/vox ... dwired.pdf

I'll get pics up as soon as I make enough room on the bench to get the head opened up.

Thanks

[KT66]

Mercury should have included the wiring diagrams with the trannys check the packaging for an envelope . If you can't find it, just give them a call on monday. The PT is probably standard color coding : 2 red wires are HV tap and Red w/ yellow stripe is the CT for that winding ; 2 greens are the 6.3V filament winding ; 2 blacks are the primary.

[power chord hack]

This set didn't come directly from MM - it was used - so no documentation.

[IMG:120:160]http://i14.photobucket.com/albums/a322/tmge/vox/th_ac15031.jpg[/img]


Check this out:
What's the thing cliped onto the leads?

[IMG:160:120]http://i14.photobucket.com/albums/a322/tmge/vox/th_ac15022.jpg[/img].[IMG:160:120]http://i14.photobucket.com/albums/a322/tmge/vox/th_ac15027.jpg[/img].[IMG:160:120]http://i14.photobucket.com/albums/a322/tmge/vox/th_ac15028.jpg[/img]

[Bob-I]

First find out which wires are connected to the same winding. A simple continuity test will tell you which wires are on the same winding. Once you have that documented you can put wire nuts on the wires and apply AC to the primaries, most likely the black and whatever is it's partner on the winding. Use a light bulb limiter and a small fast blow fuse, .5A or so. Measure the other windings carefully. I use alligator clips and connect the wires to the meter with power off, then I don't have to touch the HV AC to measure.

[power chord hack]

Bob -

So you're saying:
- determine which are the primaries
- apply limited (via the lightbulb) current to those
- measure the output of the other leads - without getting blasted by the HV


any idea about the wire clip thing?

[FYL]

What's the thing cliped onto the leads?

Looks like a large ferrite clip. Can help cut HF noise when properly used.

[Dr-Joned]

Ditto on the ferrite core. They help reduce the possibility of radio interference, high frequency interference, and eddy currents. Try and retain the same setup. There is a reason they put in the circuit and it does not interfere with the sound.

They are used in the computer and telecommunication field a lot.

[Dr-Joned]

I would also email Paul or one of the guys at Mercury. They can be very helpful and surely email you a diagram for the tranny. Just explain it was used and you want to use it.

[KT66]

Based on my experience with Mercurys after seeing the pics of the OT I can say with confidence that the blue and the brown wires are the primary plate connections and the red is the CT. The black is the secondary common, the yellow is the 8 Ohm tap and the grey is the 16 Ohm tap. Even if I didn't know that, you could figure it out logically if you assume that the black wire with the solder lug on it is the secondary common and use an ohm meter to figure the rest.

[Bob-I]

Bob -

So you're saying:
- determine which are the primaries
- apply limited (via the lightbulb) current to those
- measure the output of the other leads - without getting blasted by the HV


any idea about the wire clip thing?

I don't understand the question. Just use alligator clips so you don't have to touch anything.

[power chord hack]

Bob -
I was asking about the RF ferrite clip thingy...

...the blue and the brown wires are the primary plate connections and the red is the CT.

The black is the secondary common, the yellow is the 8 Ohm tap and the grey is the 16 Ohm tap.

Yep! Confirmed by Mercury.

BUT....

I measured the OT thus:
black - yellow = 0.9ohm
black - gray = 1.1ohm
gray - yellow = 0.6ohm

red - brown = 184.8ohm
red - blue = 191.2ohm
blue - brown = infinite

So is the secondary jacked?
Good thing this was really cheap...

(BTW I checked my meter against several resistors: 1ohm, 47ohm, 56K, 220K, 1meg - the meter is fine.)

[Structo]

Looks like the primary is open.

That's too bad, somebody probably ran the amp without the speaker attached.

[Masco]

With a lot of xfmrs, you cant get a dc resistance measurement from plate to plate. Go ahead and install.

[power chord hack]

Looks like the primary is open.

That's too bad, somebody probably ran the amp without the speaker attached.

HI TOM!!
How are things?


So, fried primary. Yay.
What about the low readings on the secondary?

With a lot of xfmrs, you cant get a dc resistance measurement from plate to plate. Go ahead and install.

You think so?
That's a bit scary...

[Masco]

Scary?

Don't worry. If the primary were open, which is probably not, nothing will happen.

Um...you do use a light bulb limitter when powering up an amp, don't you?