[Premium-Rx] hello to the list and rare Collins unit

[Peter Ratuschni]

Hello all,
I am interested in communication equipment for several years now and finally I subscribed to this list. My english is far away from being perfect, please excuse.
I worked as an electronics for Honeywell in Germany and studied physics later on. So far a some older units, mostly receivers from CEI/wj, passed my way. It started with a DRO from 1972 and the lecture of Terry`s website did the rest of the 'infection'. 

My first question goes for a real black radio accessory from Collins.
The unit is named VP-100 and according to the label on the back, it is a HF voice privacy unit. The housing is in the style of the HF-8090 or the 851S receiver. On the back there are 600 ohms connections named TB1/RADIO and TB2/LINE. On the frontplate there are a speaker, a mic input, a numeric keyboard with RCL, STO, CLR, two key switches (PVT/CLR, LOAD/OPR) and one button named ZEROIZE near to the power switch. Then there is a numeric display for KEY, SEGMENT and DATA and several status LEDs (RCV PVT, RCV CLR XMIT, PRIVAT, FAULT, LOW BAT, TEST, PUB EXCHG and even one LED not named at all (it lightened up one time).
In the unit there are 5 plugin pcbs, named TIMING, CPU, BULK MEMORY, INTERFACE and MODEM. The power supply is huge and seems that they took it from the 851S and omitted only a few parts. 
The only unpopulated slot is named TEST and therefore I conclude the unit is complete (and yes, the keys are there, even a record number and destroy tag). The only apparent damage is that leaking batteries destroyed the battery holder. The batteries should be for memory backup. They are shorted via a resistor when the unit is drawn out of it`s rack.

The problems are: 
- The LED digit display is most time dark. When the unit is switched on with the ZEROIZE button pressed, it sometimes shows something.
- There is no visible reaction from the numeric keyboard.
- Sometimes the speaker gives a permanent beep.

Does anybody has information about this unit?

- Peter