Twin Tube GFX-1

[Iperfungus]

We're making the Twin Tube's Family grow!  :lol:

I assume we'll soon be banned from the Depot...  :facepalm:

I also have an original controller and cable, but I never use it: I just tested if it works.
It's a shame that's not a MIDI controller: remote control only.
That's ok for the unit, of course: it's dedicated, no need for external power supply...

By the way, I tested the "broken" unit: it f**king works and tones are exactly the same as the other unit.
Of course, there's no holder and there's no battery there...

The bad smell and the fact that connector from transformer became hot in less than one minute from powering the unit on, worry me a lot: something is not ok somewhere.
But I'll try to fix this one as well: it's a shame to use it for spare parts and throw it in the garbage.
If only the original owner had not inverted that connector from tansformer on the main board...or if I had a better look before powering the unit on...I would have bought a working one for 30 euros ... :facepalm:

Oh, if you have the chance...try it with a Mooer Radar with Marshall-like IRs and good headphones...it will surprise you again!
And internal effects will start to make sense.

[bunkyloo]

Actually it looks like my transformer was plugged in backwards as well and still is and works fine.
Not sure why. Here is a picture showing the harness and after i swapped tubes and fixed all the problems.

[Iperfungus]

Uhm...to be honest, it looks cables from transformers to main board are not backwards but in the right position.
Exactly in the same way they are positioned on my functioning one, as far as I can see.
Anyway, I wouldn't try to reverse them...  :lol: :lol: :lol: :lol: :lol:

What about battery? Is still the original or you changed it?
Did you repair the battery holder as well?

Very good job, by the way!

[bunkyloo]

The only reason i say it looks backwards is the outline of the connector on the board and the actual connector are opposite the picture doesn't show the other side and the battery still worked so it is the same but I hot glued the battery holder. It works but I don't think I would trust it for the long haul.

[Iperfungus]

You're right!

The top connector is put upside down: opposite to the mark on the board.
I had a better look to your pictures.

On mine, the reversed connector was the other one, the bottom one coming from the MADE IN CHINA transformer.

I'm not sure, but maybe...in this case....I would reverse that connector.

About the battery holder, it looks that Keystone does not produce anymore that model.
This will make my second repairing a pain in the ass for sure.  :facepalm:

The original battery still charged is a stroke of luck.

[bunkyloo]

If you get the black heavy duty glue sticks it works out pretty solid I guess if thats all we can do. That is really a bummer about no replacement. Perhaps the Mighty MJMP has a suggestion ?

[Iperfungus]

Mouser has this one:

https://www.mouser.it/ProductDetail/Keystone-Electronics/2224?qs=%2Fha2pyFadugenAX7QbWVFAtBL7ngADIAmZuo9%252BFPgqPfH15sDT0VIA%3D%3D

It looks closer to the old one, but I'm not sure if battery will fit there.

I could try to repair the old battery holder by soldering, maybe.

The battery in yours is a Duracell??

[rnolan]

We're making the Twin Tube's Family grow!  :lol:

I assume we'll soon be banned from the Depot...  :facepalm:

Hey Max, that would be a bit harsh LoL, I'm watching on with interest  :thumb-up: and hey, Dante has one...  Interesting result with the original Chinese bottles BTW.

[Iperfungus]

Hey Max, that would be a bit harsh LoL,

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:

I'm watching on with interest  :thumb-up: and hey, Dante has one...  Interesting result with the original Chinese bottles BTW.

Oh yes....the original MP1's bottles are KILLERS.
Too much, maybe...  :lol:

AS I wrote, at the moment 7025 GT tubes are the best inside the GFX1.

[Iperfungus]

Mmmmmmmmh.....maybe I can repair the original holder, damaged by battery's acid.

Luckily I'm a kind of maniac and I saved the original holder ('cause you never know...), including the lug and the internal pin that have come off.
Plus, I'm italian and we're rich in fantasy!  :lol:
With a small screw, a nut and a couple of washers, it could work again!

f*ck Keystone!  :lol:

[MarshallJMP]

Ok seems I'm missing out on something here  So maybe I can have a look at some battery holders but I need some more info. As far as I can see it looks like an AA battery? Pins into the pcb?

BTW a battery doesn't loose acid but an alkaline. Alkaline is as bad as an acid so if it's on the pcb it will "eat" the traces so you will need to neutralise it with you guessed it with an acid. There are a lot of vids on youtube on how to do this.

[Iperfungus]

Ciao Phil!

The battery is a sort of AA, yes.
Alkaline, 4.5V, neverseenbefore format.  :lol:
Original battery no longer in production, but here's a compatible one:

https://www.amazon.com/gp/product/B00FED2M9K/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

The holder is a Keystone, No 139 with PC mount lugs.
Original one is in the attached picture, but it seems Keystone does not produce it anymore.

A similar one:

https://www.mouser.com/ProductDetail/Keystone-Electronics/2224?qs=%2Fha2pyFadugenAX7QbWVFAtBL7ngADIAmZuo9%252BFPgqPfH15sDT0VIA%3D%3D

In my case, acid from battery only damaged holder...luckily: traces are ok and safe.
The rings that kept lug and pin together and in place in the holder have been destroyed by acid.
But I kept holder, lug and pin and I think a small screw, a nut and a couple of washers could help to fix it and put it back in place.

[MarshallJMP]

Farnell and RS still carry the 139 but with solder lugs, not  pcb pins.

The battery is for the RAM backup?

[Iperfungus]

Farnell and RS still carry the 139 but with solder lugs, not  pcb pins.

The battery is for the RAM backup?

Mouser and DigiKey have the same holder (139) as well, but no pcb pins.  :facepalm:

Yes, it's the internal backup battery for RAM...to keep settings and patches while the unit is powered off.

By the way....maybe I fixed the old holder...   :lol:
It seems to work.

[MarshallJMP]

Is it held on the pcb by the pcb pins?

I think you can also use 3.6V AA battery's normally, these are  a lot easier to find.