Batboard

Hello, I have an old S-1327B Service Monitor that recently lost it's ability to lock. I cannot use it to generate or receive any signals. The lock lamp occasionaly flickers like it is trying to lock up but no go. Is this a common issues with these older units? I have another one that I thought about swapping cards out to try and isolate the issue.






Thanks
Tom / KA1NVZ
Anchorage, Alaska

The 1327 model is at least 30 years old. I think you've probably gotten all the goodie out of it that there was in it.

My two bits worth:
I used to repair and calibrate these critters. I still have several parts units.
You need to get the proper service manual. The first thing to check is the power supply voltages. At this age the filter caps tend to fail.
There are trouble shooting trees which will aid in determining which of the many VCOs is out of lock.

Be VERY careful in exchanging cards. Be sure all jumpers are the same, as well as same part number.
Do NOT use a ruby eraser on the card contacts, use Caig D-5.

The S1327 was made by the now defunct Systron-Donner Co.
The design dates to the '60s. Many of the circuits are very obsolete. Was not considered very reliable when new, I doubt that they greatly improve with age.

Like the Cushman CE-3, 5 the S1327 uses in band mixing. The 100meg steps come from a comb generator which generates harmonics every 100 meg, mixed with another VCO (one of 3 in the A-12) to generate the receiver injection frequency which is 10 meg below the dialed in frequency.

In generate, the receive injection is mixed with 10 meg from one of two 10 meg sources, in CW the 10meg is locked, in FM the variable 10 meg VCO is used to allow FM modulation.
All of this mixing results in a very dirty RF output, the desired output frequencies being much lower amplitude than some of the various other present signals. This results in many spurious results when attempting to measure or generate.
Your receiver may seem to receive on many other frequencies, you may interfere with another radio on a site when you are doing site measurements.

Should you actually rebuild this unit I would suggest replacing the time base oscillator with a modern TCXO.
This is one bit of technology that has improved greatly over the years. Surplus 10 meg TCXO should be relatively cheap.
The time base board has jumpers for various reference frequencies.

To check the VCO's on the A12, dial in a freq of 090.0000 MHz, check for lock, then 109.9900 MHz, check for lock. This is the first of the three VCO's on the A12. The lower and upper limits of the other two are 110.0000 to 149.9900 and 150.0000 to 189.9900 MHz. Usually, if the 1327 didn't lock at any of these freqs, the problem was in the time base, the phase detector or the 100 MHz multiplier. However the A12 did have a divide by "N" circuit that if it is bad, forget the repairs. The chips are definitely NLA.

Hi Guys,

I have a S-1327B with a broken deviation meter in the removable module (SLN6350A 75). Does anyone have a working module or preferably the replacement meter for this monitor?

I would also like to find a low band pre-selector module.

Thanks,

Jimmie