[Amps] Alpha 87a No RS-232

[Dick Green WC1M]

Hi Gerry,

I don't know if this will help, but RS-232 in my 87A stopped working after a lightning surge. The amp was otherwise fully functional. Like you, I operate the amp remotely (though not as far away -- it just in a closet in the basement.)

In my case, the lightning event destroyed a lot of equipment, so the cause was obvious. The surge came in on the SteppIR control cables, destroyed their driver boards, and travelled to the computer over their RS-232 connections, frying the computer, then propagated to every device connected to the computer via RS-232, including the 87A and an Acom 2000a. I believe back then I used a multi-port RS-232 card, not the USB-to-RS232 hubs I use now. Not clear whether the hubs would have saved the devices. I did have an FT-1000D that was saved by an external level converter, so perhaps the hubs would have done the same.

In most of my equipment, the typical failure mode was a fried MAX232 chip. But in more than half the cases the surge propagated through the MAX232 on a TTL line connected to the CPU, destroying it as well.

I replaced the MAX232 chip in the 87A, plus all the other support chips on the control board (just in case). But that didn't fix the problem. It turned out that the surge had indeed travelled to the CPU, but didn't destroy it because all the I/O ports are fused. Thus, only the TTL serial I/O pin was non-functional. The CPUs in the rest of my equipment didn't have this high-class feature, including the 2000A, the CPU of which was completely fried.

Unfortunately, I needed the RS-232 function and it isn't easy to replace the CPU because each one is individually calibrated to its amp at the factory, setting such things as the stepper motor positions and fault detection voltages. My 87A is one of the older ones, circa 1995. Alpha downloaded the calibration parameters for all the amps made back then, but later the computer or hard drive where they were stored was lost or destroyed, and they lost all the data for all the amps, including mine. I don't know if parameters for later amps were saved. Not long ago someone posted a neat procedure for capturing the parameters to a file, which I have used to insure against a future CPU failure. Without those parameters, the amp has to go back to the factory. I had it done at an "Alpha Day" in Bedford, NH that K1RX had very fortunately (for me) arranged for YCCC members, and was able to skip shipping the amp to Colorado. I was able to wait while Brad fixed my amp. I can't recall all that he did, but I believe the procedure involved some special equipment and about a half hour to an hour to perform. [N.B. I was also able to drive the 2000a to Krassy's factory and wait while it was repaired, but that's another story.]

Given that both 87As can't talk, I'd speculate that you had a lightning surge, but the question is why it didn't affect any other equipment connected to the computer, of which I imagine there's a lot in a remote station. Have you checked everything else? I'd be interested in hearing more about your investigation into that.

Hope this helps.

73, Dick WC1M

-----Original Message-----
From: Gerry Hull <gerry at w1ve.com> 
Sent: Monday, July 2, 2018 7:49 AM
To: amps at contesting.com
Subject: [Amps] Alpha 87a No RS-232

Hello All,

We have two Alpha 87as at K2LE.   They have been rock solid amps for
decades.
However, we operate remotely, and rely upon RS-232 using the great DF3CB software.

We have the same failure mode in both amps.   The TX side of the serial
port has failed.   We can command the amp on,
But that is it.   We have verified multiple times and multiple ways that
the cable and ports are working perfectly (short TX/RX Pins on the amp-side connector and ensure echo on a terminal program).

I see very little about this subject in the archives.  Has anyone else experienced this?

Does anybody know if the Max232 chip is soldered?   This is what I suspect,
since the amplifier is fully functional otherwise.

Is there some master reset we can try with a combo of front panel buttons?

Your collective wisdom appreciated.

73, Gerry W1VE
For Andy, K2LE and the team


--
Gerry Hull, W1VE  Hancock, NH USA
Member: ARRL, YCCC, YCCCN, CW Ops
gerry at w1ve.com ph: 1-617-CW-SPARK (find me)