Searching for Information
We were unable to find any information whatsoever about the radio from the Internet. We also tried to email Zycomm Sales and Tech Support but received no replies – not even automated responses.
Finally, we even emailed Ian Sneap, former boss of Zycomm but he couldn't help either.
We posted a request for help on the “UK Vintage Radio repair and restoration” forum, & one of the guys there found a thread from 20 years ago about the Zycomm 5016, wherein Dom G7NPW suggested he might have some information. Found G7NPW contact details on QRZ.com and reached out
Dom G7NPW very kindly found the service manual and scanned it for us.
He says they are fairly easy to setup; you have to program the EPROM - set VCO Voltage and tune RX front end and PA.
Reviewing the manual supplied by G7NPW, which looks exactly correct in the cover illustration, we found that the PLL circuit differs from the one fitted into our Zycomm.
Circuit from Manual
Our Set
The circuit in the manual in based around a Plessy NJ8812, whereas the one we have is based on a Motorola MS145146 PLL, a MC14161B counter, and a 4069
However, we noted the part number of some of the cards given in the manual and after some (rather random) Google searches I found some other Sets which appear to have the same card fitted.
So, this is getting very interesting, and I wondering if these are generic cards, fitted into various badged Transceivers
I found this
And then this:
http://www.radiowrench.com/sonic/so02209.html
The one of the most interest is badged as a Neutec unit. This has a PLL card based on the Motorola chip sets, featuring a Dual modulus pre-scaler chip.
I also spent some time on the Control panel circuit comparing between the Zycomm and the Nuetec. G4XRA modeled these in NI Multisim to check the functionality as this forms part of the of the Eprom addressing circuit