Print

[KW4CQ]

In the middle of exchanging a report on 20m using FT-8 my Acom 1000 (6 months old) suddenly shut down showing Auto protectio: TR2B.  Not exactly sure what this means except that it has resulted in no off air signals being received by my IC-7610.  If I bypass the Acom amp and connect coax straight into the 7610 receive and transmit is AOK.  I have power recycled the Acom amp several times but no luck.  Could anyone point to the possible cause?
Many thanks,
73 Bob KW4C

[W0CKI]

Bob, download the full manual and go to; trouble shooting. 6.5. You will learn the TR2 has to do with your antenna relay. It's probably stuck.
How much power were you running on FT8?
An email to Val at Acom would be a good start.
HNY, Gary W0CKI

[K7JQ]

Pages 39 and 40 of the manual will explain the problem. TR2B:

"Antenna relay tests made while changing from RX to TX (during Operate mode). Output relay closed (ORC,logic)".

The fact that there's no receive when antenna goes through the amp confirms that the relay is not permitting transfer to RX when not transmitting.

I remember having some occasional TR6B and TR4B hard faults when I had an A1000, but in those cases I was still getting signals through to the xcvr on RX.

 

[KW4CQ]

Thanks to you all for the suggestions on what to look for.  It does appear that it is either the output T/R relay or the logic associated with it.  I'll get a note off to Val at Acom to see if he might be able to offer some specific tests to perform.
73 Bob KW4CQ

[VE7RF]

Thanks to you all for the suggestions on what to look for.  It does appear that it is either the output T/R relay or the logic associated with it.  I'll get a note off to Val at Acom to see if he might be able to offer some specific tests to perform.
73 Bob KW4CQ

If you have lost the RX, then it's either the output relay, and / or the INPUT relay.   The NC contact of the input relay is run over to the NC contact of the output relay.  On RX, you should be seeing zero ohms from the center conductor of the input coax connector..... to the center conductor of the output coax connector.

The COM might be welded to the NO  contact on either/ both relays.   It could also  be the bias relay.
It could also be any of the logic that controls the relays.

[ZS5WC]

 ;)Hi Duty Cycles and digi modes are a nightmare for amps.
Most amp outputs should be derated when running digi modes, which in most cases is not ICAS service.
Maybe TR relay contacts are welded?.

73 de William,
ZS4L / ZS5WC

[N4ATS]

Just curious , when the amp cooled down , did it function as normal again? FT-8 is quite deadly on amplifiers of ALL types. I get them in the shop quite frequently with heavy damage due to running FT-8

[KW4CQ]

I contacted Acom tech support and together we determined that the vaccume T/R relay had in fact had stuck contacts and has to be replaced.  Cost for one shipped from the plant in Europe is approximately $270.oo.  OUCH!  Are there any Acom parts suppliers in the U.S.?  I could also us a new band switching knob.

[W3SLK]

KW4CQ said:

I contacted Acom tech support and together we determined that the vaccume T/R relay had in fact had stuck contacts and has to be replaced.  Cost for one shipped from the plant in Europe is approximately $270.oo.  OUCH!  Are there any Acom parts suppliers in the U.S.?  I could also us a new band switching knob.

I don't have said amplifier, (I wouldn't mind) but you might want to try here with Dr. Alex for a less expensive alternative: http://www.ur4ll.net/#relays

[VE7RF]

I contacted Acom tech support and together we determined that the vaccume T/R relay had in fact had stuck contacts and has to be replaced.  Cost for one shipped from the plant in Europe is approximately $270.oo.  OUCH!  Are there any Acom parts suppliers in the U.S.?  I could also us a new band switching knob.

Acom uses cheap greenstone Vac relays. Val at Acom sez they have a 30% failure rate, right out of the box....(they test em before installing in any amp).   Jay at Array solutions sez he has replaced hundreds of vac relays in Acom amps...and the greenstone vac relays are junk.  Jay replaces em all with a GIGAVAC  GH-1 .  The Gigavac  GH-1  is the same as a Jennings  RJ-1A  or a Kilovac  HC-1.  The only difference is, the Gigavac GH-1 uses a metric sized threaded base...which drops right in where a RJ1A /HC-1 once stood.   Moot point, since the greenstone uses metric threads as well.  The Taylor brand of vac relays is another one to avoid.

Note,  you can buy the GH-1 with either a 12 vdc coil (80 ohm coil)....OR a  26.5 vdc coil (335 ohm coil).  Buy em from Max Gain systems in Georgia.  https://mgs4u.com/product/gigavac-gh-1/   
$124.95   It's at the far right on the 1st row.  https://mgs4u.com/product-category/rf-components/vacuum-relays/spdt

Acom buys the cheap Chinese clones for $55.00 each in bulk.  Dunno why they waste their time...with a 30% failure rate when they arrive......and a huge failure rate out in the field on the relays that initially pass inspection.

Note, the Gigavac GH-1  consistently hi-pot tests to 7.5 kv, which is beyond superb. ( hi-pot rating is 5 kv, on the Gigavac GH-1..and also the RJ1A + HC1).   

Years ago, Alpha used to use the Jennings RJ1A...then later switched to the Kilovac HC-1.  Reason was the HC-1 has more robust inner guts, when relay used for  QSK  CW.  The GH-1 is better than the HC-1.    HC-1 is still used today in the UK made SS amps.   Kilovac HC-1 is still available today, but stupid expensive.   I have used all of the brands, and stick with the GH-1...and buy em a dozen at a time.


To recap, what u DON'T want is the VHC-1   https://mgs4u.com/product/vhc-1/

[KM4AH]

Since the price for new has gone so crazy I have been buying pulls off of eBay, usually from Israel.  Haven't lost one yet.  But, I don't do FT-8 or QSK either.

For $125 the ones from Max Gain look good.

[K7JQ]

I contacted Acom tech support and together we determined that the vaccume T/R relay had in fact had stuck contacts and has to be replaced.  Cost for one shipped from the plant in Europe is approximately $270.oo.  OUCH!  Are there any Acom parts suppliers in the U.S.?  I could also us a new band switching knob.

You said the amp is 6 months old. I assume it’s an older amp that is “6 months old” to you? Otherwise, I’m sure you know it would be under warranty.

[KW4CQ]

Yes, I see that one now from Max Gain Systems and I will order one when they open tomorrow.  Earlier in my string I misspoke, my amplifier is actually twenty six months old, not six months old,  and out of warranty.  Sorry about the verbal typo.
Flashback:  I think I know what caused the failure in the first place.  I wanted to check the tuning on the amplifier before using it and hit the WSJT-X Tune button while the amplifer switched to the wrong band.  There was a loud chattering of relays coming from the amplifier and the HF Autotuner which lasted several seconds.  The amplifier went into error alarm and shut things down.  The hf autotuner was not harmed but the amplifier's T/R relay must have welded closed its contacts. 
OPERATOR ERROR 
Again, thanks one and all for your support.

[VR2AX]

What is the best practice relay spec difference between QSK (relays operating often) and FT8 (heavier average)?

[VE7RF]

What is the best practice relay spec difference between QSK (relays operating often) and FT8 (heavier average)?

You want fast for qsk, which is any GH-1, RJ1A, HC-1.   Typ they are 2-3 msecs. When sped up, they are all 1 msec or less.

All 3 of those relays are rated for 7 amps CCS @ 32 mhz. (2450 watts CCS).  FT-8 won't blow em up.  I designed a 2 x GS35B 6M amp for a fellow.  He used 3 x new gigavac  GH-1's.   Input, output + cutoff bias.  Handles 5 kw on 50.125 mgz to this day..and was built > 10 yrs ago.  Runs like a top.
What will trash relays is high swr, like no load, no ant, wrong ant, shorted ant,  etc.  Or an auto tuner trying to 'tune'.

This is why I use external high swr protection  (which open off the TX inhibit lead in the xcvr)  and also the adjustable spark gap across the vac load cap or in the case of a SS amp, right at the output.

In the case of a tube amp, and an adjustable spark gap across the load cap ( air varaiable of vac cap) it will protect the load cap and the vac output relay.  I also put a 2nd adjustable spark gap across the tune cap...which also protects the tune cap and the band switch.