atcomsystems.ca/forum Forums Other TDM Phone Systems Other Telephones & Systems Need some info on MELCO LABS K19 Product

I am looking for anyone familiar with the K19 Intercom box produced by Melco Labs in the early 80's. I have the installation instructions. My customer is using this as a campground intercom, and it has developed a ground hum that is rendering it useless. They are using it as a stand-alone intercom with modified 2500 and 500 sets. If anyone is familiar, drop me a line and I'll explain the problem in detail.

Thanks!

Something of that age I would wonder if it is a ground hum or ac voltage getting into the DC talk power.

I think Merritt is on the right track

how many stations ?

I have some MC-9's new in the box , if your interested PM me

Ooh, I have one of those in my warehouse as I couldn't bear to just pitch it in the dumpster.

You can take a butt set and listen to the A battery for external noise. A lot of times, when the power supply starts to go South, you'll hear the lack of filtering in the battery supply.

Probaby your best bet, is to test the system without any amps connected. Either make a pigtail for a single station, or just test the battery for noise with the cables unplugged. Then, it's just a matter of isolating all the stations until you find the bad one, if the KL is not bad.

A small sum of ca$h will pry this unit from my hands if you need to replace it.

Carl

To add to the correct suggestions: open the A battery (Talk) supply, and listen for the hum. If it hums, you can add a 1000mfd electrolytic filter capacitor on the output leads. Observe polarity.

If the supply is not the problem, you must isolate each T&R and test for a metallic problem, until you find the offending wire.

Are you familiar with telephone testing procedures and tools? If not, someone can walk you through the procedure. The power supplies, and intercoms and others like it are often available on the E-place.