Variable PSU for coil tattoo machine

Thread Starter

oramics

Joined Nov 3, 2020
10
Hi.

I've been asked by my tattoist if i could build him a Variable PSU for his various Coil tattoo machines. I'm out of my depth really. So thought I'd ask here in case anyone could point me in the right direction. Today i tried a couple of LM317 type variable circuits, which were ok. The transistor got incredibly hot very fast which made me think I'm missunderstanding what circuit I will need (i hadn't attached a heatsink to the transistor).

My electronics experience is mainly building audio equipment, synths etc... and some motor contol circuits. This has all been Analogue.

The reason my tattooist asked is because he's had various digital PSU's that eventually fail on him. His requirements thus far have been for it to be variable, stable and for it to have a visual representation of what voltage it is runnning at. I was surprised i couldn't find schametics on the internet, which is why i'm here asking.

Thanks in Advance

Darren
 

MaxHeadRoom

Joined Jul 18, 2013
26,289
First you should find out the current demand of a working tattoo unit, this will give you an idea what device you need, IIRC they use a simpe vibrator mechanism.
Do you have an old/defective PSU unit you can diagnose?
 

Thread Starter

oramics

Joined Nov 3, 2020
10
Hi, thanks for your reply. I am told it requires 1.5a. but I will hook it up to my bench supply tomorrow and current test it properly and report back.

I had a defective PSU on my bench for the past few days, but it was digital and SMD, both of which i don't know about. I did get it working though. I can't exactly tell what its fault was, but I'll try. Upon opening the unit I could see a scorch mark on the PCB inside and two empty solder pads, above it the component that was meant to be soldered to the pads had welded to the lid of the PSU. I don't know anything about the PSU/Controllers previous life, my tattoiost had bought it recently off ebay and was having it fail on him. I got it working today by simply making sure the welded component couldnt make contact with anything below as I think it was that was shorting the unit out some how. I had it runnning for two lots of 40 mins today with no problems and couldnt force it to fail by applying too much pressure to the unit. I know this all sounds very bodge it, and kinda unashamedly it is. But i sat him down today and explained all this to him so he is aware, and have advised him to get his money back from ebay.

I am due to be delivered two analogue faulty units in the next week or so so i can look at them.

best

Darren
 

Thread Starter

oramics

Joined Nov 3, 2020
10
Hi. I measured the current draw on this type tattoo machine today. It draws 800ma at 12v. It does however make my bench supply sag to around 10 volts when I drive it up to the 12v. I asked him yesterday what voltage range he likes to run this machine at and he said, between 4.5v and 12v.

Rear binding post and front binding post are where the power is supplied to the machine.
Thanks

Darren
tattoo coil diagram.pngtattoo coil wiring.png
 
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