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Lexicon Prime Time Model 93

8/7/2003 6:28 PM
Mark Black
Lexicon Prime Time Model 93
Hi all -  
Does anyone have any service documentation at all (schematic at least, calibration/testing even better) for this elderly digital masterpiece?  
 Or is it destined to join the MXR Digital Delay Mod 113 in the "Waiting for Duplicate Working Unit to Test Against" pile?  
 Already tried Lexicon - no joy. It always makes me sort of "shake-my-head-in-wonderment" when the manufacturer has no documentation at all of something they used to make, especially when it's a piece that helped put them on the map...  
 Thanks - Mark
12/14/2003 10:26 PM
Mark Black

Hopeful bump...
12/17/2003 4:44 PM
Mark Black

OK I just thought I'd update this in case it helps someone else.  
Never underestimate the power of percussive diagnostics!  
This unit was powering up and passing dry signal but had no delay effect from either of the two sections.  
In sort of absent-minded exasperation I tapped in various places around the PC boards with the handle of a small screwdriver and whoa - it started working! Only momentarily of course but long enough to let me know the problem was probably one of a mechanical origin.  
I eventually localized the source to a PCB interconnecting multipin and found the plating was shabby and coming off the pins with a touch, so probably had some measure of resistance in the connection. After cleaning up this trouble spot (also some scratchy controls and a few dubious solders) the unit is back in operation.  
Gee - maybe I need to take a small hammer to that MXR next... :-)
1/11/2004 12:37 AM
Rick Erickson

"Gee - maybe I need to take a small hammer to that MXR next... :-)"
You mean you haven't yet??? That's a standard troubleshooting tool here. I call it "controlled shock" therapy. A Boeing surplus soft face dead-blow hammer from the interriors dept. works well. :)  
If that's the old blue panel MXR DDL with the plug-in memory expansion cards I may have some service info in my files. I remember having to take them apart every couple months on the road to clean all the connector contacts. They were pretty touchy units - didn't like dust, dew or extreme temperatures very much. How's everything at Northern Light & Sound?  
1/21/2004 7:04 PM
Mark Black

Hey Rick - I didn't see your reply.  
Yup that's the old blue-face rack-mount unit all right. It would almost be better if it was stone dead but instead it's noisy and I can actually see the stairstepping of the D/A on the output at low frequencies.  
It has the extra memory card so I was able to rule out bad memory by unplugging one & switching the card count jumper (unless they're both bad exactly the same way).  
No joy for me in terms of tapping on this one - it seems to have a legit problem.  
My experience on all-discrete digital delays is limited to this one so far and I guess I keep hoping another will come along so I can do some board-swapping to localize. As you probably remember it's pretty tough to get a probe in there with the cards plugged in and operating.  
The store is doing OK (thanks for asking). GC and the internet haven't quite been able to drive us out of business although they certainly have lowered the bar on profits. How's things with you?  
12/25/2003 12:32 PM
Rich P
Service Manuals / Schematics Diagrams / Operating Manuals ...  
... KUSTOM, KUSTOM VOLUME IV, 54.00, 1, kustom amplifiers vol IV. LEADER, LBO-520A, 48.00, 1,  
LBO-520A LEADER OSCILLOS. LEXICON, PRIME TIME 93, 60.00, 1, Lexicon Prime Time 93. MEGASTAR,  
HP-K7000, 34.00, 1, HP-K7000 Megastar servic. MOOG, MICRO/MULTI MOOG, 30.00, 1, Moog Micro  
- Moog Multi. ... -  
Good Luck!
12/28/2003 1:57 AM
Mark Black

Thanks for the reply Rich.  
I had never noticed those guys have a lower minimum order for documents. The $100 (Canadian) minimum for parts orders has caused me not to order from them many times in the past so I tend to surf right past their site anymore.  
Well I guess the point is moot now since the unit is working and back at the local music store for sale.  
Thanks again -
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