Cheap cash register with a dead transformer

[Toasty]

Re: Cheap cash register with a dead transformer

I understood that. Realize they won't run the reg, but battery backup in a sub-$100 register is just surprising. I've seen ones that cost $1,000 not have that.

[dood]

Re: Cheap cash register with a dead transformer

Interesting.. I'm not familiar with registers at all. Didn't know that battery backup was that unusual.

[Toasty]

Re: Cheap cash register with a dead transformer

It's not that it is unusual. The fact it is in such a low priced unit I found unusual.

Get it fixed yet?

[dood]

Re: Cheap cash register with a dead transformer

It's not that it is unusual. The fact it is in such a low priced unit I found unusual.

Get it fixed yet?

Yep, swapped the xformer out of one of the other registers, and all is well.

One down, two more to go!

[Toasty]

Re: Cheap cash register with a dead transformer

R U DUN? It's THURSDAY!!!

[dood]

Re: Cheap cash register with a dead transformer

Got the 2nd working... Actually ended up using the internals of the one I stole the xformer from. I really wish he just would've given me all of them at the same time... The 3rd one I got had dead keys, but even after I cleaned the circuits off, it was acting weird. All the keys responded normally, but it would freak out and blink the screen and run the receipt printer at random times. I took the keypad and transformer off of it, and transplanted into the other, which just had a few dead keys. So, he got 2 working registers back, and is happy

He has a 4th register, so I hope to be able to make that one work too, but it's not the same model as the others.

[Toasty]

Re: Cheap cash register with a dead transformer

The freak out could be too much ripple on the line which the CPU beats with its own freq.

-or-

There's a margarita under the keyboard. Literally.

Check those ribbon cables when you can. A little corrosion where it plugs in to power/logic board, or under one of the chips.

Good job! Hope you were well compensated for the ER work.

Toast

[riotpack]

Re: Cheap cash register with a dead transformer

Look at the V regulator on that heatsink and see what type it is 7805 etc. Look at the electrolytic capacitor voltage after the bridge rectifier and you should get a rough idea what the transformer voltage was. Say the Electros are 16V then you could assume the transformer would be 9VAC (9*1.414=12.726V DC) and not 12VAC as that would be greater than 16VDC. As for current, well the peak of course would be when that motor kicks in and from what I see and from the existing Xformer would be less than 1A peak.

[dood]

Re: Cheap cash register with a dead transformer

The one that was freaking out had been thoroughly doused with beer. The keyboards clean up easily with some water and alcohol (ironic), but I think the mainboard took a hit. Or at least shorted when the beer was applied, and messed something up. I couldn't see any physical damage to the mainboard, and I wasn't looking to put too much time into these by tracing circuits, etc.

I was compensated in the form of a few tasty craft brews...

[riotpack]

Re: Cheap cash register with a dead transformer

I have seen liquids hide under ICs and remain conductive causing problems, sounds like noise getting into the logic(cpu) side of things and the high Z sections (like the Xtal) can easily be influenced by even high resistances. It doesn't have IC sockets does it? regardless it may be good to get some parts from