Write-in problem STD2-Entertainer

[Gerhard Vermaeten]

Hello,
I'm trying to fix a STD2-Entertainer. When a selection is made, the mechanism scans twice, picks up nothing, and stops. Known as Tony Miller's 'Symptom 3'. I followed his instructions: Write-in voltage is 121V (not 125V but I assume that's normal), battery-test is normal. My conclusion is that there must be a write-in circuit problem. I don't see a voltage-dip when I make a selection after credit. I checked the circuit with the temperature compensating resistors in the Tormat, 190 ohms, so the ground return must be ok. I have to check the triggering device but that is for me, I'am not a technician, hard to do. I opened the grey box. Somebody did that before so I don't know the quality of the box. How can I check the triggering device? My plan is to replace CR3228 (1N5257A ?) and CR 3229 (??). That is quite easy to do. Can someone tell me which zeners I have to use (original or subtitute)? Than I want to replace Q3207 (2N6027 ?) and Q3208 (??). Here also the question, which transistors I have to use? All advice is welcome ...
Gerhard, greetings from The Netherlands

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[Ron Rich]

Hi Gerhard,
You do not want to change anything on the board with the "chip' (235 board)--- I hope you used anti-static procedures when you opened that box ! The zeners on it are used as "fuses"-- if there has been no over voltage of the -13 and -13, those are not even "in the circuit". You have the latest version of both boards--If a bad DRD, the problem is usually on the lower (033) board, in the main trigger SCS. Do you have a copy of my "Seeburg MicroLog Trouble shooting Guide" ? Do you have a copy of the late Tony Miller's "Black and Grey box book". Your problem could be anywhere from the DES, DTP, DCC, or DRD-- which is the very last suspect ! You should trouble shoot it prior to changing parts.
Ron Rich