ARP Solina String Ensemble PE-IV -1974    Weight= 46.2 Lbs. or 49 w/cover Number mfg.= ? MRP=$?

Circuit Overview:
      (Note: The synthesizer version is very rare..only 100 produced I read. Haven't seen one) Divide down from TOS with a lot of waveshaping like Omni etc. The Solina String ensemble is one of the first string machines to appear on the market. (See the story of Ken Freeman's machine which should have been first (and used 25 HF oscillators) but due to an Organ company that just didn't want to pay the engineer what he was worth, they lost their market share as the Crumar Stringman and this unit hit market first!) It has an AR envelope with controls and bass and total volume along with the preset buttons. The envelope though has kind of a pulse attack then crescendo which is kind of unique. EARLY models used the SAH190/SAJ110 tos/divider combination. SAA1030 or M087 TOS appear in later units (I was in error on this prior) but the one I repaired ~2011 had a more common M50240P but the board for the M087 was used! Was this done at the factory or did an individual cut all the traces and hard wire that chip in? I have no documentation so if anyone knows on this one let me know! Mine also used the SAJ110 red divider chips with offset pins; most of which were not working right. (On a more recent one they were all working. Bad production runs?)

Service Tips
     Probably a lot of tantalum capacitor problems like Omni though I've not seen many yet. I worked on one that had lost output and turned out they used a 741 in the 14 pin package I think I recall. Glad I didn't throw those away! :-) I'm working over one of these which has a lot of differences from the diagrams I can find. It has mostly 8 pin 741's in it and so I'm going to have to do a lot of beep tracing apparently to figure where things go. Three of the sliders were removed and fortunately Kevin Lightner had exactly three of these 37-8mm travel units and...they were the exact three values I was missing! What..are the odds of that? Most ARP sliders are 44mm or like that and of course you can't get anything but 45 and 30mm usually from venders. THey are CTS parts still.
     St. Eric notes that the tuning coil on these is 54uH should anyone run into that problem. Oddly on my unit it wouldn't nearly come into tune but I see no coil damage. ALL resistors are within spec it appears. An NTE128 was residing in the transistor location though and an NTE199 is the actual cross for what was in there which is much higher gain! I skeptically put one in and as I suspected it had no impact on the situation. Worse if anything as I'd have guessed since it's way SHARP. So I checked values of the other caps and the nearby electrolytic was 1.5uf instead of 1. But that had no effect of course since they wouldn't use an electrolytic in a tuning circuit probably. So I wound up just putting a poly 50pf across the coil and that knocked it down to where I was able to pull the core of the coil back out where I want it. I just don't see what caused that!
Ok..the divider chips. I'm tring to imagine how someone kept playing it with 5 failed and then said 'hmm that 6th one is just to much!' hehe. Anyway I installed sockets with LONG PINS because you have to bend the pins a ways for the in/out pattern of this version of the SAJ110. (Ie. they are a standard dip package but they've offset the pins so that..they can be probed more easily? I dunno why. But it's a lot of extra work putting those sockets in!) NOW I AM NOT SURE WHY but MANY of the SAJ110's that tested ok in a Crumar Organizer2 would fail on the *same pins* as the ones I took out of the unit. Lower frequencies in general. Anyway I ALSO lowered the voltage a little since it was at about -10V or more and I figured it could be -8.5V probably without hurting anything quality wise. The max rating on these chips is -11V I see. VERY CONFUSING because as you see on the diagram is says -12V but that I assume is for the SAA1004 chip which I have no specs on. FINALLY as I was about to sell this unit..another failed. OUt of all the SAJ110 chips I had plus another 7 I scrapped out of something that probably worked fine...ALL of them failed on the same legs which were used for the lower E or F depending whether I put them in on chip 6 or 7! The thing is..I could find chips that would work in one location at 7.5V or less..and the other at 7.6 or more! IE. I was .1 V tolerence from having a working unit. It would work briefly at 7.6V then start making horrible noise again. I'd put in a local cap even and it did no good. THE SOLUTION? I scrapped out an orchestrator and got the SAA1004 chips out of it. Replaced the two questionable ones and all was good. I'd recommend any roaded machine at least carry some sockets with long legs that can be bent in place of those 'jogged' pin 14 pin packages...and some SAA1004 chips.