Ballantine 5500A counter, seeking info or manual

[zike]

[sorry for re-post, evidently I put this in the wrong forum topic at first]

Also known as the "Accumetronic" (!). Hoping someone has a manual gathering dust to loan/scan/sell. Docs for similar 5500B (later, non-Nixie tube, 110 MHz) may serve.  Usual boat anchor manual sources came up dry.

This brochure  indicates the unit is "fully programmable" by way of a connector on the rear panel, but it turned out this option is not present. Banana jacks found in the place of that connector were for an external "elapsed time" TTL input.

OTOH, aforementioned brochure indicates 6 digits with 7 optional, whereas my unit has 8 functioning nixie tubes (!?). It also appears to trigger well past 70 MHz.  So maybe this is a later "A" model.

Also curiously, while Ballantine was/is in New Jersey, my unit was evidently built in Germany. Both problems I've found so far are "West Germany" labeled electrolytics that failed in a dead short, one in the 5V supply (mains fuse protected the rectifiers, fortunately) and the other timing a multivibrator in the gate system (gate wouldn't close).

I'm still trying to track down a problem with the front end; all functions appear to work with TTL-level inputs, but she won't fire on anything smaller than 2 volts. Hard to troubleshoot without proper schematics.

Hope someone can help,

Zike

[zike]

Status update (success!):

- Ballantine responded right after the holiday. They do still have the original manual and offered to sell me a copy; but they actually scanned and emailed me a full set of schematics and parts lists (8 triple-fold B-size pages) for free!

- It is evidently not indexed, did not come up in search, but Oliver Pogensee has the full manual for the later 5500B. This has 7-segment LED figures instead of Nixie tubes, and thus, e.g., a different readout board and no 200 VDC supply; but it is otherwise very similar.

(Interestingly, this download bears the K4XL "BAMA" mark, but is absent from the preserved mirror of that archive...?)

- The "MHz" enunciator bulb was burned out. I bodged in a red LED and a resistor ;^)

- Once in a while the clock oscillator seemed to just quit. I reflowed joints in that section of the main board and it hasn't recurred.

- Trigger issue was a failed (open) "preset" switch on the A trigger level pot. Bypassing this (and rebalancing the front end) gives me solid triggers on 50 mVrms sine up to ~120 MHz, and on 300 mV pulses down to about 7 ns width.  Better than spec.

- While I was in there... added a wire from "RESET" back to the (unpopulated) remote interface connector plate, and installed a second pair of banana jacks. So now I have both "elapsed time" and "reset" remote inputs on the back panel. 

- Counter is fully working now. Not about to replace my 5316A; but them nixies sure do look purty.

zike