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-   -   Tamiya tank gun barrel flash not working (https://www.rcuniverse.com/forum/rc-tanks-369/11671949-tamiya-tank-gun-barrel-flash-not-working.html)

craggle427 11-15-2019 07:39 AM

Tamiya tank gun barrel flash not working
 
Hello all, first post here....

I have a Tamiya 1/16th Tiger 1 tank which I purchased many years ago and used trouble free for quite a few years. The NiCd batteries then became tired so I took the tank apart with the view to change them and re-paint the tank at the same time. Unfortunately life got in the way so it was packed into a box and put away until last weekend.
I have now purchased new 2s Lithium batteries for it, connected everything up again and it all works great except the gun muzzle doesn't flash. I have the orange light on the MF-01 unit and I can hear the high pitched whistle of the flash unit charging when you turn it on. When firing the gun I get the sound, the gun recoil and the tracks jump backwards as it should but no flash. I have tried with freshly charged NiMh batteries from my Bullhead truck too but no difference.

I have taken the flasher out the barrel and removed the heat shrink covering on the flash bulb and the capacitor like thing half way up the cable but can't see any obvious broken cables or other damage.

Do you think the problem is with the flash unit (£50 to replace here in the UK) or could it be a problem with the MF-01 unit? Does anyone know of a way to test the systems without spending out £50 on a new flasher?

Many thanks

Craig.

RichJohnson 11-15-2019 10:07 AM

I have to say i have not had good luck with tamiya flashes. On a new pershing it flashed fine for a few days then dropped to every other fire then every 3d fire. I pulled the sherman flash and tested it in the pershing system with the same results. It was the mf. I put them all back and the psershing system dropped to random pattern when it would light so I pulled it out and gave up.
if you hear it charging it might just be a bad bulb, i would try ebay for a spare flash unit.

heavyaslead 11-15-2019 11:40 AM

Verify the connector and pins that plugs into the DMD unit, I have had pins partially push out such that connection is loose.

craggle427 11-16-2019 02:01 AM

Thanks for your help guys

Been playing again this morning and still no luck. I plugged in the connector and pushed the back of each pin in with a small screwdriver so pretty sure the connection is good now.

I unclipped the top of the MF unit expecting to Find a relay with contacts I could clean in it but no so luck, all solid, surface mounted components but it does look very clean in there, no corrosion on the tracks or anything.

Looks like finding another flash bulb is my only option of just go without it. I have seen quite cheap Heng Long flash units with a similar looking bulb on the end, wonder if I could adapt one of those to fit?

Cheers

Craig

tomhugill 11-16-2019 03:18 AM

The news mfu units had a component that was underspec and would fail. I had 3 kv-1 mfu where the flash failed. A chap in the UK repaired one of my mfus with a better component and it's been fine since. If you're in the UK I can send you a flash unit to test if you pay postage both ways

Tankhobby 11-16-2019 06:08 AM

Usually these circuits have a coil to generate a large voltage using an oscillator circuit, this voltage is across the two ends of the glass tube. There is a trigger wire on the glass between the two ends. This is what makes the tube light when it is driven with another high voltage. If we can identify the "bad" component it should be an easy fix. Caution that high voltage can hurt!
Alternately a surplus camera flash can be substituted, but this would be involved because you would need to wire it in to trigger off the MFU. I did a project a while back and I believe there was a Heng Long flash unit available that I used for an 88 gun flash. It was an easy hookup if I recall correctly. That may be another option.

Shorty54 11-16-2019 06:33 AM

If the new Taigen or HL flash could be wired in somehow, that would be ideal. They are available and reasonable $$.


Shad

tomhugill 11-16-2019 08:15 AM


Originally Posted by Shorty54 (Post 12564122)
If the new Taigen or HL flash could be wired in somehow, that would be ideal. They are available and reasonable $$.


Shad

Completely different setup

craggle427 11-20-2019 01:23 AM

Thanks again for you input everyone

I decided to take the flash unit and the MF unit along to a local electronics workshop where I know one of the chaps there. We hooked it all up and tried firing the gun and was convinced we saw a tiny flash. Turned off the lights and yes, there was a tiny flash but certainly not the full flash it should be. We tried a few times then got a bigger flash and smoke between the trigger wire and the glass tube.

We measured the voltage across the contacts on the ends of the tube and that was around 300v so that seemed okay and as we saw some flashing we guessed the high voltage trigger was working as well so came to the conclusion the bulb or flash tube had probably leaked and failed.
I have been looking around for a replacement tube to solder in place and my research has led me to cheap, disposable 35mm film cameras with flashes. Apparently they also use a 25mm long flash tube and they can be bought for less than £10 here so I'm now thinking I'll get one, take it apart to recover the flash and see if that works. I have found just the flash tubes for sale in Europe and the US for only a few pounds / dollars each but postage to the UK immediately adds on another wedge of cash.

I'll keep you posted if I get this sorted out

Craig.

heavyaslead 11-20-2019 05:01 AM

Thanks so much for the forensic !

The tube leaking over time (introducing oxygen into the bulb) is something I never thought of - thus the smoke

craggle427 12-03-2019 04:04 AM

Thought I'd finish this thread off in case anyone in the future finds it useful.

I got my cheap, single use camera a while ago in the post and set about taking it apart. It was a Kodak Funsaver camera and it comes apart pretty easily with clips on the side holding it together. Taking it apart reveals a pretty standard roll of 35mm film already would and ready to use. Off course the film is exposed to light soon as you take the cover off.
Anyway, not after the film, after the flash unit. That too is only clipped into place and a soldering iron soon had it released from the camera and soldered in place of the Tamiya one on the gun barrel harness. It is the same length but smaller in diameter but looked much the same thing. The trigger wire was part of the camera clip so the original Tamiya trigger wires was unwound and re-wound around the new flash bulb. Original orange heatshrink was refitted and sealed again with very thin clear heatshrink over the top.

Plugging everything back together I heard the whine of the capacitor charging up so I fired the gun and hey-presto, a big bright flash from the gun. Fired it a few times and all seemed well.

I kept the soldering heat to a minimum so I didn't affect the bulb but not sure how long it will last. Hopefully all camera flashes are made to the same standard and will flash a 1000 times or so before failing but it did come from a 36 exposure camera so if it does 36 flashes it has probably done it's job. I think these cameras are recycled as well going back to the manufacturer for a new roll of film so maybe it will last longer than I think, fingers crossed.

Craig.


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