[GreenKeys] Connecting 28 ASR to a TU

[tokens at myranch.com]

It turned out that IC1 (709N) was defective. I replaced it and now apparently all is well, I get meter deflections while playing ITTY. Next I will have to hook up the 28ASR and see if I actually get copy. I did find it strange that an apparently never used ST-5000 would have a defective IC but that seemed to be the case.

Thank you all for your comments and suggestions.

73,
Al W8KHP

From: tokens at myranch.com 
Sent: Wednesday, October 11, 2017 11:37 AM
To: greenkeys at mailman.qth.net 
Subject: [GreenKeys] Connecting 28 ASR to a TU

I recently acquired a 28 ASR  and have it working locally. Problem is getting it to copy off the air. I obtained two TUs with hopes that they would be in working condition. One is a Hal ST-6 and the other is a Hal ST-5000. The ST-6 was kit built with modifications. It arrived with all the boards rattling in the box. When I opened the chassis every board was loose. The ST-5000 looks as if it is brand new. It arrived in its original box with all the original cables and connectors waiting to be made up. My assumption is that with either one of these TUs if I fed in a rtty signal I should see deflection on the meter. I have tried itty from the internet connecting to the line out of the computer and I have tried rtty off the air connecting to the line out of the receiver. In both cases I see no sign of meter movement with either TU. I know there is a signal being fed into the TUs as I can connect to a separate scope and see the deflections with the signal. At this point I don’t know if I have two dysfunctional TUs or whether I am trying to use them incorrectly.

Any help would be welcomed.

Thank you.

73,
Al W8KHP


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