Quoted from Lovef2k:
No that I know you have an Alltek lamp driver here are some easy things to check.
1 is the board grounded to the back back via screws to the mounting brackets?
Yes, although the bottom-left screw board mount screw is stripped out, both screws appear to be getting good connection. pic attached
Quoted from Lovef2k:
2 is the grounding strap from the base cabinet attached to the grounding post in the bottom of the back box?
Yes, although the grounding straps are just hand-wound together, they all do connect in the backbox and appear to be getting good connection. pic attached
Quoted from Lovef2k:
3 are you using LEDs in this game? If so, is the jumper from the lamp driver board connected and what is it connected to?
Add pic of connection if possible. If it was tied into the GI circuit that may cause big problems.
No LED's being used, no jumper strap, reference lamp bord pic again.
Quoted from Lovef2k:
4 verify the connectors on the lamp driver are not off by a pin. I know they are keyed but you never know if a key fell out or someone had changed a connector in the past.
I verified this again, all connectors are attached correctly, referencing keys in each. Although none of the original IDC connectors are broken or appear to be burned out, I do have a "Big Daddy" molex connector repiar kit I could install but have not.
Quoted from Lovef2k:
Run switch test when you get a chance. It won't take but maybe 10 to 15 minutes.
I finally ran the switch test. all switches are working, 36 (right slingshot) and 37 (left slingshot) have to firmly be held in to register their corresponding numbers, but do open and close OK with a little force.
Other updates:
A. on my "Good" EBD, I did correct about 6 SCR transistors on the OEM lamp driver board, so now I am confident in my ability to check transistors for correct/incorrect operation, read schematics to identify the corresponding playfield light, and replace the transistors.
B. After a couple good loud games when the kids weren't sleeping- I determined that the Squak & Talk board is playing the correct sounds, BUT- the Speach sounds are normal volume and the "Game play" sounds are very muted. I swapped it out with my recently re-capped S&T board from the "good" machine and verified that problem. I have another cap kit from Big Daddy enroute and will do that when it arrives.
C. I looked the playfield over closely and although there are a few not-so-great looking repairs from the past, I can't positively identify any place that is shorted. But as a relative "beginner" I probably don't have the best eye for that. One of the previous owner's repairs was a rectifier replacement to the transformer board. I measured the Test Points (TP) and the only one out of range by a significant amount was TP3, which should be 11.9 +/- 1.4 and measured out at 15.45 VDC. pic of repair attached. Could this be an issue?
again, I'm a relative beginner at electronics repair, but I've always heard difficult to identify problems are sometimes determined to be a "bad ground" or hard-to-find short circuit, so that biases me toward that situation here.
Thanks for all the help to date- I'm learning a lot here!
Dan's EBD alltec lamp driver (resized).jpgdan's EBD ground strap connection (resized).jpgDan's EBD transformer module (resized).jpg