Twin Tube GFX-1

[rnolan]

@rnolan: Rich, Fabrizio is attempting to register to the Depot...but new users registration is suspended. I suggested to use the NEED HELP button and to shot you an email.

Hey Max, I got your email, done  :thumb-up:

[MarshallJMP]

I have no clue but I did swap all 3 components. Also that was without the battery installed.
Installed the battery and  pin 2 is 4.67 and pin 8 is 4.85. Sorry for the misunderstanding. Steve

Do you have a battery with a lower voltage? like a 3V or 3.6V.

[bunkyloo]

I found a 3.6 volt AA size on amazon. Do you think that will work?

[MarshallJMP]

It should work, the RAM is the same type used in the MP-1 and that works on 3V. For some reason the IC won't switch between battery power and main 5V. Although the difference is now more than 50mV it still doesn't seem to work. Strange.

[Iperfungus]

Hey Max, I got your email, done  :thumb-up:

Ciao Rich!
Yes, I saw!
Thank you very much!  :thumb-up:

Fabrizio knows a lot about Digitech stuff and he did a lot of work and modifications on those units in the past years.
Maybe he could be of help here!

[bunkyloo]

Just installed the new battery the 3.6 volt and it powers up no problem , so now just seeing if it will save a patch unplugged. Just so annoying I can't use the OEM battery UGGGH.
Thanks for the help all especially MJMP. If Fabrizio has an idea I am all ears Thanks guys. Steve

[MarshallJMP]

Ok keep me updated. Also strange that the 5V is not in spec, should be at least 4.9V, can you measure the volatge at the 7805 between pin 2 (ground) and pin 3 (out), also between pin 2 and 1 ?

[bunkyloo]

Well got too excited, as soon as I tested the unit powered up battery installed it read pin 1- 7.18 and 3-4.99 and then it crashed while testing so I tested battery in and 1 was5.15 and 3 was 3.642.
I then tested no battery and 1 was 5.54 and 3 was 4.04 and now won't boot with the 3.6 volt battery. :facepalm: .

[Iperfungus]

Well got too excited, as soon as I tested the unit powered up battery installed it read pin 1- 7.18 and 3-4.99 and then it crashed while testing so I tested battery in and 1 was5.15 and 3 was 3.642.
I then tested no battery and 1 was 5.54 and 3 was 4.04 and now won't boot with the 3.6 volt battery. :facepalm: .

It looks that unit is playing jokes for (its) fun.  :facepalm:

[Harley Hexxe]

It looks that unit is playing jokes for (its) fun.  :facepalm:

    I think the Flux Capacitor gave out :dunno:

[bunkyloo]

Well it may just end up for parts backup if we can't get it sorted. I hope its not the flux capacitor that's only available in 1985 I believe  :lol:

[MarshallJMP]

Try this, get the battery out and measure over the battery connections.

[bunkyloo]

It starts at 0.7 and continues to drop

[MarshallJMP]

Did you start the unit?

[bunkyloo]

Yes I did start it and it responds the same either way.