Midi Problem: Loose all programs when turning off amp

[kka]

This is an older Diezel VH4: When I program and store just simple ch switching (ch1 on 01, ch2 on 02, ch3 on 03 of Midi controller board) it works perfectly, but after turning amp off all programs are lost and I have to start from scratch again.

Does die Midi chip inside the amp store the programs for the controller board that was used, or does the controller board store this information?

I don't understand exactly how this works.

Thanks for any help provided.

[eschertron]

The volatile memory is on the board, and my guess is that there's a battery somewhere also on the board that retains the data after power-down. I'm not familiar enough with that piece of equipment to tell you what kind of battery, or even if it can be changed out without a soldering iron, but there's a battery.

[kka]

Thanks for the reply. Here is a pic of the Amp's midi board. There is a round lithium battery. Is that what needs to be swapped? This amp is 13 years old...

[eschertron]

at thirteen, the battery is well past its prime

see if you can cross reference it, or find a manual or parts list to get a part number. It looks like the battery can be removed fairly easily (I don't see any visible solder tabs), there might be a part number on it, also. Good luck with the replacement!

[kka]

I found a replacement with the same dimensions:

Tadiran TL-5186 Waffer Lithium Battery

Hope this works. I would have to flip the board over to desolder the old battery, but that is easy to do.

Thanks again.

[Enzo]

And you can verify with your volt meter if the old battery is holding a charge or not.

[Fragger]

Some of these batteries have impressive life. Last weekend I hooked up my old Yamaha Dx7 synth bought in '85 and unused for the last 4-5 years. A system check showed 2.4v on the original internal battery and all the user programmed internal voices I feared lost... still sounded. (That`s 28 years!)

[Enzo]

I seem to recall them saying that 2.2v was enough to retain memory.