English Mark Darts Help

cnyncrvr

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Hey all new here and looking for some help / advice.

A friend of mine picked up a 1986 Arachnid Super Six Series 6000 machine for $40.00 bucks on sunday. when he got the machine home it wasnt working and asked me to come take a look at it as I have some decent experience with electronics.

First thing I did was download and print the parts manual. When I got over there it was determined that rats or mice had at some point made a home out of the machine and chewed through some of the wires and just royally made a mess of the entire cabinet.

Cleaned everything out, which was a chore since we removed everything from the machine and gave it all a thorough cleaning with a stiff brush and some compressed air. Put everything back together and hooked everything back up, checked all the fuses and they were all still in tact and able to flow current.

Plugged the machine in and the lights around the target head came on but nothing else, No sound, No video, no lights for the throw or remove darts, none on the coin slots, and none on the select or player change buttons.

Also as soon as we plugged the machine in TMS4416 in slot U13 started smoking, thats always a bad sign, so we unplugged the machine and swapped U12 with U13 and no smoke. So I know I have to replace the memory chips, Also since the machine was an original series 6000 that did not have the dip switch on the logic board and had a rom version of 2.0 I have decided to replace the battery backed MK48Z02 ram since im sure the battery is destroyed.

I ran some tests and found that the linear power supply was intermitedly supplying 12 volts but not constantly so for testing purposes I swaped out the original power supply with a switching power supply from an old desktop computer. hooked up the 12 volt leads and 5V leads as well as grounds and the 21V to a 12V. Now the bottom Remove Darts light came on but no other lights, No sound and no Video.

With the fried TMS 4416 ram chip and a dead battery on the MK48Z02 Should I still get some kind of video signal, lights, or sound out of the machine?
 
On the power supply board, bridge rectifier BR1 is the main source of troubles. It rectifies the AC and feeds the filtered raw DC to three different voltage regulators:

One for the +5 volts for gameboard logic and coin/credit board logic.

One for the +12 volts @ 2 amps just for the internal 9" monitor power.

One for the +12 volts @ 1 amp just for the 12 volt lamps.

Suggest measuring all the output voltages at the power supply output connector to be sure all are present.

If either video ram chips U12 or U13 (TMS4416) go bad, replace them both. Also when one of those TMS4416 chips catestrophically fails, it frequently will take out the main video processor U11 (TMS9118) with it.

Additional information:

http://www.leagueleader.net/bullshooter/support-3/legacy-products-2/6000-series-dartboards

http://arcarc.xmission.com/PDF_Darts/Arachnid/

http://home.comcast.net/~mtpacifico/_kenskorner/kenskorner.html (scroll down to the darts section)
 
Last edited:
Hey Ken thanks for the reply!!

Would having the 4416 chips fail cause there to be no sound or lights from the game? or do they mainly only work in the video circuit of the logic board?
 
Check the power supply voltages first since it is THE most troublesome unit in the machine.

Then check the cpu chip U3 (a type 6809 microprocessor) and these chips:

U4 and U17 PIA (both are type 6821)

U15 game eprom (type 27256)

U16 (type 6840)

U23 (type MK48Z02 battery backed ram chip)
 
Hi Ken, thanks for the help so far, been out of town for the weekend so im just now getting around to looking at the top board on the PSU. Is the transformer on the PSU an isolation transformer? I ask because I removed the top board on the PSU today and undereath someone had soldered a jumper wire from the BR1 bridge rectifier to the first white leg connector coming out of the transformer. With the Jumper wire in place the first leg reads 12 volts but if I remove it I show no voltage coming out of that leg?
 
People often put in too large of a fuse going to the bridge rectifier which often burnt the traces off of the power supply board. That's probably the reason for the jumper wire. Always replace a fuse with the correct size and rating.
 
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