[Amps] Alpha 87A troubles with fault 17
Dick Green
dick.green at VALLEY.NET
Fri Jan 23 15:03:27 EST 2004
Andy,
I don't know if all Kenwood rigs have the problem. It's been quite a few
years since I had the 940 and I can't recall if I had fault 17 problems with
it. If I did, they were not as numerous as the problems I had with the 950.
I don't know how W8JI measured the leading edge spikes on the 950. I think
he would have to use a storage scope.
I don't think the 950's ALC problems are necessarily limited to the T/R
transition when PTT is pressed. It is certainly possible that the rig has
problems controlling speech peaks. Most of my problems showed up on CW or
vox SSB, so we can't compare. Another possibility is that the speech
processor is misaligned. Can you drive the problem with and without speech
processing? It's certainly possible that there's nothing wrong with the ALC
or speech processing and that you have the mic gain or processing turned up
too much. It's very hard to see big, fast spikes on the 950's meters when
your voice gets momentarily louder. If you have a good peak-reading
wattmeter with a variable hold delay you might be able to determined what's
going on by putting it between the 950 and 87A.
I do not agree with the person on AMPS who said there is something wrong
with the 87A. The amp is doing its job -- protecting the delicate and
expensive tubes from a potentially damaging drive or load problem. The only
"bug" is that the firmware reports the wrong fault code -- 17 instead of 13.
If it really is 13, then the rig is producing large spikes. This could be
due to rig design flaws, misalignment or improper front-panel settings.
However, just to make sure, you should connect the 87A directly to a
kilowatt dummy load to make sure there's no arcing in your antenna system
(i.e., that it really is fault 13 and not fault 17.) Another way to convince
yourself is to borrow another brand rig (I'd suggest Yaesu) and see if the
problem goes away.
I've had good luck speaking with Alpha (Crosslink) people on the phone and
via e-mail, but it's been quite a while since I've done that. Glenn is very
helpful, so if he's still there keep trying to get through. However, I would
do some of the above tests before consulting with Glenn. No need to bother
them if it's a rig design problem.
73, Dick WC1M
> -----Original Message-----
> From: Andy Forsberg [mailto:CS-Imaging at prodigy.net]
> Sent: Friday, January 23, 2004 9:47 AM
> To: dick.green at VALLEY.NET
> Subject: RE: [Amps] Alpha 87A troubles with fault 17
>
>
> Hi Dick,
>
> I had a conversation with Dick Ehrhorn before I bought the
> Alpha and it seems to me you are right about the trouble with
> Kenwood 950's.
>
> That raises the question, is it all Kenwood's or just the
> 950. I also Have a TS-2000 and it faults 17 also. How did
> W8JI measure the leading edge spike? When I get a fault 17 it
> is not at PTT but some time later and without speech
> dropouts. In other words the mike is keyed continually. No
> Vox. The fault 17 can occurred several minutes into the
> transmission. This does not seem like leading edge spikes,
> unless they occurred at speech peaks.
>
> Some people tell me they have resorted to 3 dB attenuators to
> solve the problem. This my work but you should not have to do
> this on a TOP OF THE LINE amplifier that you just dropped
> $6500 on. There's something wrong with that picture. I guess
> I think it should work out of the box the first time.
>
> If this is a firmware bug it seems like that could be fixed
> relatively easily. Which comes back to CrossLink's business
> practices. Not good. John suggested to phone. Has anyone ever
> gotten a warm body on the phone at CrossLink. I have never
> gotten a return phone call and have never ever reached anyone
> with a phone call. I did however talk to Glenn on one
> occasion while in trouble shooting mode.
>
> Thanks for your comments, I will follow up with, sic.... Alpha,
>
> 73 Andy WW7A
>
> -----Original Message-----
> From: Dick Green [mailto:dick.green at VALLEY.NET]
> Sent: Thursday, January 22, 2004 9:35 PM
> To: 'W0UN -- John Brosnahan'; 'Andy Forsberg'; amps at contesting.com
> Subject: RE: [Amps] Alpha 87A troubles with fault 17
>
>
> I used to have this problem when I drove my 87A with a
> TS950SDX. It's caused by a power spike from the 950. W8JI
> told me that he had measured leading edge spikes from the 950
> as high as 250W. The reason you are getting fault 17
> (abnormally high or low gain due to possible mismatch or arc)
> is that the 87A firmware checks for abnormal gain before it
> checks for the overdrive condition (fault 13.) In other
> words, the misleading fault number is a minor bug in the
> firmware. I confirmed this with the factory. Dick Ehrhorn
> told me that he had the same problem and confirmed the fault
> code anomaly with the Alpha techs. I think Dick was using a
> 950 also, but I'm not sure.
>
> I have since replaced the 950 with a Yaesu FT-1000MP,
> followed by a Yaesu FT-1000D, followed by a Ten Tec Orion. I
> have not seen a fault 17 since getting rid of the 950.
>
> 73, Dick WC1M
>
> > -----Original Message-----
> > From: W0UN -- John Brosnahan [mailto:shr at swtexas.net]
> > Sent: Thursday, January 22, 2004 6:11 AM
> > To: Andy Forsberg; amps at contesting.com
> > Subject: Re: [Amps] Alpha 87A troubles with fault 17
> >
> >
> > Don't do emails when trying to sort out amp problems--it takes too
> > long to get to the heart of the matter. It is much better
> to call the
> > manufacturer. A two-way dialog usually discloses some sort
> of issue
> > that would NEVER get mentioned in a two-way series of email
> exchanges.
> > From my personal experiences on both ends of
> trouble-shooting, a phone
> > call is 1000% better to get to the solution quickly.
> >
> > --John W0UN
> >
> >
> > At 08:48 AM 1/21/2004, Andy Forsberg wrote:
> >
> > >Hi All,
> > >
> > >I have a TS 950 and TS 2000 driving a New Alpha 87A. I am
> > continually
> > >getting fault code 17 in SSB while talking which puts the amp into
> > >standby mode. The amp is tuned properly either using
> > default, manual,
> > >or AlphaMax. Nothing seems to help. Alpha factory will not
> > return my
> > >e-mails so I have know idea how to get these radios to drive
> > the Alpha.
> > >When I took the amp out of the box at turn on I got a hard
> > fault 24 and
> > >the amp would not come on line. After two power ups I
> finally got a
> > >green board. The first time I applied 20 watts drive power
> > it faulted.
> > >That cleared I was finally able to get the amp to full power and
> > >sic.... operational. The fault code 17 (extreme
> miss-match) started
> > >right away and have not stopped. I can not get through a
> > transmission
> > >without a fault 17 occurring.
> > >
> > >I understand that Icomm 781's had this problem also? Are these ALC
> > >overshoots? Can they be prevented? Is this a problem with Alpha or
> > >Kenwood? Either way the amp is useless as long as it keeps
> faulting.
> > >
> > >Thanks for any help the group can offer,
> > >
> > >73 Andy WW7A
> > >
> > >Latitude N 47.35 degs
> > >Longitude W 122.95 degs
> > >
> > >_______________________________________________
> > >Amps mailing list
> > >Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/a> mps
> > >
> > >
> > >
>
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