Hello all. I have a Tamiya Pershing and I think I may have blown the recoil control 'curcuit?' in my DMD unit. I did something incredibly stupid when I was charging my battery unit. I accidentally plugged the AC from the charger into my tank and turned it on. I realized the mistake and disconnected, and everything seemed okay. That is when I noticed that my barrel continuously does a slow recoil and return cycle. Everything else works fine. In fact, the quick recoil still functions when I activate the firing switch, but it also does this continous, slow recoil loop now too. It does this as soon as the battery is connected. I have tried reseting the DMD as per the Tamiya instructions but with no luck. The self test also shows no problem. I have researched the forums but haven't found any clues there. Anyone have any suggestions?

The recoil starts moving as soon as you connect the battery.... even with the power switch off? if so then yes you have fried the DMD/MF if not you may want to try another recoil unit just to confirm its the DMD/MF.
For testing purposes you can plug any tamiya recoil unit in.

If you still have the receipt call tamiya customer service tell them the symtoms they may send you replacements. Electronics especially expensive electronics are supposed to protect themselves from overvoltage.... If you don't have the reciept still call them I had missing parts for a T1 I received for christmas and they let me fax the cover of my manual as a receipt.

A long shot, but check the limit switch on the gun carraige is still making/breaking contact. This stops the gun from recoiling more than once after firing.

Good point about the limit switch. I had the same problem with my King Tiger. This can be easily ajar and can be easily fixed. I can almost quarantee this is your problem.

Even if everything looks good with the limit switch making/breaking contact, it's still possible that the switch is burnt out, that happened to me, the symptoms were as you described. I haven't found a drop in replacement switch yet.

If you decide to open/inspect the limit microswitch be careful , the spring can go flying when you open it, I never saw mine again! But that didn't matter because the switch was fried anyway.

Thanks for all the replies. I did as heavyaslead suggested and checked the switch. It was still in place and making contact, but not stopping this weird movement. It does still limit the gun carriage to only one recoil shot though when I fire the gun so it is still doing that. It's weird because I would assume it would be "all or nothing", meaning it would either stop all movement after one revolution in the mechanism or it wouldn't stop any of it anymore. So I called Tamiyausa in California and on my 2nd call I got a helpful guy who trouble-shot it with me and issued me a return number for the recoil, DMD and multi function units. I mail them out insured today. I'll keep you all posted.

TANKDUEL, your problem was exactly the same? The tank fired okay but when not shooting, the recoil would slowly cycle continously? I don't know much about the ins and outs of electronics but how can the switch still do it's main function but allow this movement?

good to hear about the RMA from Tamiya - Good customer service is important.