BandidoII Umax (Original PCB) Help

[MaineDigger]

I obtained a Bandido II umax in bad, but working condition. I cleaned it up and replaced a few switches from another machine and verified they were the same. The threshold knob was broken and I dont have a replacement yet

Is the threshold required for disc operation? When I power on the machine, it just screams. I thought I soldered everything back properly, but perhaps I missed something? Anybody heard of this happening?

Many thanks,
Steve

[Mike]

Some Suggestions

Hello Steve,

Is the threshold required for disc operation?

From my understanding of the Bandido schematic, I'd say no, the threshold does not effect disc operation. It's there to set the threshold volume for all metal operation only.

When I power on the machine, it just screams.

I'm not sure what kind of test kit you have access to, or what testing you have already done, but this is how I would start if I had the machine infront of me:

1. Check again that the disc switch is definitely working, and the detector is being switched into disc mode.

2. Check the connections between PCB and the coil (search head) connector on the control box. Use a DVM to check for continuity (detector switched off).

3. Try connecting a known good coil and check the effect.

4. If you can't get a known good coil, then check out the coil you have. If you have access to an inductance meter, check the coil parameters are correct. Otherwise, at least use a DVM to check the resistances. The values are posted here: http://www.thunting.com/cgi-bin/geot...oils/index.dat I don't know the pin-out of the coil connector, but you could work it out by comparing the schematic (http://www.thunting.com/cgi-bin/geot...uMax/index.dat) vs. the PCB vs. the connections to the coil connector.

5. If the problem is not with the coil, or the connections to it, then the electronics need debugging. This is a mixed blessing, since this going to be more complex, but if you find the problem the fix should be relatively cheap. If the coil is shot, you will probably have to scrap it and buy a new one. More expensive but easier to solve. Making one is quite complex, and probably not worth it unless you're very enthusiastic. The coil may be salvagable if the problem is just with the connecting cable, however.

To debug the electronics, you're going to need access to an oscilloscope. If you're not familiar with one, it may be easier to find someone several thousand miles closer to you than I am who can help you with the investigation. Getting help via the forum will be more long winded, but a solution may still be possible.

I'd be interested to know any outcome.

Have a good weekend,

Mike

[MaineDigger]

Thanks Mike

I appreciate your suggestions. I put this on the backburner for about a month, but am going to re-visit it tonight after work. I'm now looking for a pinout diagram on this machine to make sure I have ewverything hooked up properly. WIther that or maybe some pictures of the B2Umax similar to the one I attached (Golden). I'll let you know how it goes.

Thanks!
Steve