FT-100D UHF/UHF (2m/70cm) Power Amplifier Repair

[n6...@aol.com]

Request info on a '6-land' (if possible) repair source for the 2m/70cm transmitter final amplifier of the Yaesu FT-100D.

 

(Had sudden loss of transmit power on 2&70, accompanied by foul smell!)

 

bt73Pete, N6ZE 

[Ph...@kd7zd.us]

Good luck.  It’s my understanding the transistors aren’t made any more.  Let us know how it works out for you.

 

Phil

KD7ZD

--
~The Voice of the Pacific NorthWest VHF Society~
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[Dan Smith]

I and many know Kuni here in WA. Yes he is not in 6 land but he is one of the best. Great work, fast turn around. The guy knows what he Is doing. His web site is www.w7jv.com you can send him a question on his web site and ask him about your radio. He will know for sure if the parts are still made or not. Look up Comtek on QTH.com many happy people have left comments on his repair jobs. He has done two for me and I have been very happy with his work and prices. Sorry I don't know anyone closer, but ask some people on PNWVHFS and I am sure you will get 

more comments on him. 

73

Dan/KD7UFF

Forks, WA 

CN77

Sent from my iPod

[KA...@aol.com]

A Local Ham (KC7PPD) at my Marina has a FT100 that has a Bad T/R control IC. Supposedly VHF/UHF Final Transistor is good.

Calls to Repair techs across US says a Half Power substitute avail. for $150. If anyone still has the original transistor, it is $250 +

 If you want Original type, let me know and I'll pass along your offer to buy KC7PPD's radio as a parts rig.

 

Thomas D. Popp - KAØTP
Portland, Oregon

http://lists.topica.com/lists/PDXHamInfo - Portland region Ham news
To Join: send an email to PDXHamInfo...@topica.com

[KC7I]

> Request info on a '6-land' (if possible) repair source for the 2m/70cm
> transmitter final amplifier of the Yaesu FT-100D.
>
> (Had sudden loss of transmit power on 2&70, accompanied by foul smell!)
>

I had one of these with the same problem. Turned out to be a resistor in the
SWR sense had cooked. There are four of them, so I replaced them all with
higher ratings.

To see if this might be it, watch the ALC. If the SWR resistor is cooked,
the ALC will show way up even into a dummy load.

Bill, KC7I

[n6...@aol.com]

Hello Bill:

 

ref: your e-mail of Friday, 18March2011

 

The FT-100D VHF/UHF power module worked fine on Friday.

 

The Ft-100D VHF/UHF power module is inop on Saturday! ALC indication appears to be normal. SWR 'meter' shows 1 bar; power output 'meter' shows no bars (but nearby repeater is accessed OK); High SWR indicator in top left corner is NOT displayed.

 

Could you send me a sketch or description of location of the 4 SWR bridge resistors?

 

Thanks.

 

bt73Pete, N6ZE/K1FJM 

[Loren Moline WA7SKT]

Pete,

I am wondering what year this radio was made. Someone said the power modules are not available anymore.

We ran into this kind of thing in the process control equipment. Buy something and in not too long they quit making parts. We always said we either bought the only one or the last one made.

I think we as consumers need to as a mass contact manufacturers and tell them how upset we are that they don't carry parts for years to come after a radio goes out of production. Tell them that we will take a serious look at this lack of repair parts when purchasing a radio in the future.

As much as you could use the input signal of the power module for a 1296 transverter or other band IF if you can't get a part, I know you don't want just a partial radio.

Good luck!

 
Loren   WA7SKT
 
Member: ARRL and Pacific Northwest VHF Society
Member: Hearsat Satellite Monitoring Group ( www.hearsat.org )
Location: CN86cx                                                                                       
                          
                                

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To: bi...@kc7i.com; PNW...@googlegroups.com

Subject: Re: [PNWVHFS] FT-100D UHF/UHF (2m/70cm) Power Amplifier Repair

Date: Sat, 19 Mar 2011 13:22:38 -0400
From: n6...@aol.com

[Ph...@kd7zd.us]

My understanding at the  time was that the PA transistors were no longer manufactured.  It wasn’t a Yaesu problem it was a supply problem.  This was 4-5 years ago.  I have no idea if this is the way it is now.

 

Phil

KD7ZD

For more options, visit this group at http://groups.google.com/group/PNWVHFS --

[k3...@hotmail.com]

Yaesu fixed my dad's 2 years ago

Sent via BlackBerry by AT&T

---

From: <Ph...@kd7zd.us>

Sender: pnw...@googlegroups.com

Date: Sat, 19 Mar 2011 15:13:40 -0700

To: <lmo...@hotmail.com>; <pnw...@googlegroups.com>

ReplyTo: ph...@kd7zd.us

[KA...@aol.com]

2 months ago, a friend from my Marina, gave me his FT-100 to check operation on. No power out to dummy load. Called Yaesu and told it was $250 when they had the part, but out now. "Yaesu does not service FT100 at all now."

 Called around. Burghardts' sevice tech said correct part not available, but a low power version was.

 

HamRadio Repair in Texas explained to me about the low power substitute. Also suggested setting it up with a bypass of the finals ( 1 watt drivers) and use an external Amp with it.

 

Thomas D. Popp - KAØTP
Portland, Oregon

http://lists.topica.com/lists/PDXHamInfo - Portland region Ham news
To Join: send an email to PDXHamInfo...@topica.com

 

[Mike]

Hi Pete,

This is the long answer ... I bought my FT-100D in late 2009 and knew
it already had the symptom you described. Failure of the SWR resistors
causes a similar symptom, since it causes the PA drive to shut down,
but am guessing this is not the cause in your case.
If the SRF7043 VHF/UHF PA fails it shorts c-e. Since the supply is
connected to it, even during receive, it draws several amps until a
trace burns out, probably the cause of the 'foul smell'. The unit I
have was initially sent to Yaesu who removed jumper J502, disconnected
the VHF/UHF output coax xfmr (to prevent the heavy current drain) then
returned it to the owner saying that's all they could do, as the
SRF7043 was no longer available.

After removing the PA xtor, I tried bypassing the PA, using just the
driver; 2m output was 1.5w, with 250mW at 70cm and no attempt at
matching the antenna. I had to buy 500 volt SMD film capacitors (which
Yaesu had removed) to do this ... I guess they protected the PA from
antenna static. I was concerned the less rugged driver would be more
susceptible to any SWR problems so junked that idea.

There have been many efforts to replace the SRF7043 by other devices,
with marginal success, due mostly to the PA oscillating. I was able to
find a near replacement, the MRF1570, which almost fits but needs some
(delicate) surgery to its heat sink. After this repair and adjusting
the PA quiescent current, my FT-100D has been working OK. It can even
put out higher power than the original but I have it throttled back
using the internal menu. Some who tried this were not as
successful ... there is a stack of 4 tiny SMD capacitors between the
PA collectors which are critical and need to be carefully removed,
saved and reinstalled after the repair.

In August 2010, a ham (VU3PAT) on the Yahoo FT-100 newsgroup, found a
source in China for the SRF7043 and made a bulk buy for many users
who were able to fix the above problem. You may find somebody who
will repair an SWR resistor problem but they are unlikely to tackle
the PA transistor problem ...

I told you it was a long answer .... ;-)

73, Mike
KB7W

On Mar 18, 1:12 am, <P...@kd7zd.us> wrote:
> Good luck.  It’s my understanding the transistors aren’t made any more.  Let us know how it works out for you.
>
> Phil
> KD7ZD
>

[Bruce Junkin]

Hello All,

I solved my problem with my FT-100D. I sold the unit and bought an FT-857D.
In my opinion, the FT-857D is a much better radio with more options than the
FT-100D.

Bruce, KI7JA CN85RL

Hi Pete,

73, Mike
KB7W

> Good luck. It�s my understanding the transistors aren�t made any more.

[Mike Bond]

Hi Pete,
If the PA works sometimes then transistors are not the problem ... these rarely go intermittent!
Intermittency is usually mechanical; attached photo shows a loose connector on the PA board that caused a similar problem. There is also a relay RL5016 on the LPF board that could be sticking ... it is used only on VHF/UHF.

Below is an email on the SWR subject; the resistors are on the PA board. It says this fixed a problem on all bands , but I don't see how it could affect VHF/UHF as the SWR circuit for this is on the LPF board.  Note that this repair is only applicable if symptom is an ALC problem. I have not experienced this.

You need to look for other symptoms:  Does a high SWR or ALC reading appear on the display? If total transmit current is, say  >10amps, then problem is a connector or LPF section. If less than, say 3amps, then problem is loss of drive. Is everything normal for the HF bands?

If PA transistor replacement not needed then Yaesu or Burghardt will probably agree to repair.

73, Mike
KB7W

Re SWR resistors:

I'm posting this to this group because I've received 3 e-mails from
Prakash (VU2PKX) asking which smd resistors were replaced by
Burghadt's to fix the very high ALC FT-100 problem which resulted in
no TX power on any band... becuase I've sent him 2 replies direct and
he apparently hasn't received them.

The smd resistors that Burghardts replaced were R3034, R3035,
R3038, and R3040 which are all 5.6K ohms. They also replaced
R3041 and R3042 which are 6.8K ohms. According to the service
manual... all 6 of these resistors are located on the bottom side
of the PA Board. So the PA Board would have to be removed in
order to replace these.

*** NOTE: before you do this... make sure you do the tests that
have been mentioned in this group to make sure you
have an ALC circuit problem.

So... hopefully VU2PKX will now get the info on which smd resistors
were replaced by Burghardt's. If there are any hams in this group from
India that knows VU2PKX... then forward this message to him to make
sure he gets it... since he apparently isn't receiving e-mails that I send
to him.

Mike - N1EVH


On 3/20/2011 10:45 PM, n6...@aol.com wrote:

I have found Q3505 SRF7043 on page 79 of the service manual (F2 and 3), but can't find the 4 SWR bridge resistors on the schematics and/or the board layout pictures.

Any hints??

 

bt73Pete, N6ZE

 

PS: Today, Amp section worked for a couple of transmissions, then quit again. Also worked briefly later in the day. Frustrating!!!!!
..

---

[n6...@aol.com]

21MARCH2011

 

Hi Mike:

 

Will check later today. 4 inches rain here yesterday.  It is easy to open panels on FT-100 when it still installed in my pickup truck when not raining!!. Will also use Bird & ammeter to collect data!

 

On 2m when the final does not appear to function, I see 1 bar on SWR & no power out: very local rptrs keys up OK.

 

On 70cm when final appears not to function, I see no bars on SWR & no power out: local rptr does not key up.

 

Will look for RL5016. I wonder if the relay is replaceable???? 

 

ALC appears normal so far.

 

I downloaded big Service Manual last night and have access to block diagrams, schematics, & IPB.

 

bt73Pete, N6ZE in DM04ne today

[Snort...@aol.com]

Is this the same output transistor listed in the e-bay add I came across.  SRF7043 seemed a bit pricy

at 161.84  but I guess if you need it.    hope this helps   KG7P   Stan...

[Stephen Hanselman KC4SW]

I know they seem pricy, but the old rule of thumb for transistors was a dollar a watt

 

Steve KC4SW

--

[n6...@aol.com]

22MAR2011

PLEASE NOTE REPLIES BELOW IN 14 POINT FONT.

-----Original Message-----
From: Mike Bond <mvb...@spiritone.com>
To: n6...@aol.com
Cc: PNWVHFS digest <PNW...@googlegroups.com>
Sent: Mon, Mar 21, 2011 8:09 am

Subject: Re: FT-100D UHF/UHF (2m/70cm) Power Amplifier Repair

Hi Pete,
If the PA works sometimes then transistors are not the problem ... these rarely go intermittent!

Intermittency is usually mechanical; attached photo shows a loose connector on the PA board that caused a similar problem. There is also a relay RL5016 on the LPF board that could be sticking ... it is used only on VHF/UHF BANGING ON THE RELAY DOES NOT MAKE ANY CHANGES. ALSO, WHEN I KEY THE MIC, I DO NOT FEEL ANY MECHANICAL CLICK  WHEN TOUCHING THE RELAY CASE..   I could not find any loose connectors, particularly in the area you noted on the jpeg.

Below is an email on the SWR subject; the resistors are on the PA board. It says this fixed a problem on all bands , but I don't see how it could affect VHF/UHF as the SWR circuit for this is on the LPF board.  Note that this repair is only applicable if symptom is an ALC problem. I have not experienced this.

You need to look for other symptoms:  Does a high SWR or ALC reading appear on the display? I DO NOT GET HIGH SWR &/OR ALC ON THE DISPLAY.If total transmit current is, say  >10amps, then problem is a connector or LPF section. If less than, say 3amps, then problem is loss of drive. RX CURRENT ~2 A; XMT CURRENT WITH FINAL NOT WORKING ~3 A; HARD BANGING ON CASE OCCASIONALLY GIVES NORMAL OUTPUT & NORMAL ~20A DRAW FOR BRIEF PERIODS OF TIME Is everything normal for the HF bands?  HF/6M ARE NORMAL AT ALL TIMES.

 

TEMPERATURE DOES NOT APPEAR TO BE A PLAYER.

 

Thanks for your continued help!!

If PA transistor replacement not needed then Yaesu or Burghardt will probably agree to repair.

73, Mike
KB7W

 

BT73,

Pete, N6ZE

 

[Mike Bond]

Hi Pete
Sounds like a loose connection somewhere around or before the driver.
Do you have another rig or receiver that can monitor 2m or 70cm?
If so, can it detect a signal when you key the FT-100?
Forgot to ask you if it's receiving OK on VHF/UHF?

73, Mike

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[Jeremy Alexander]

Good choice Bruce,

The 897d is probably the most popular IF radio on the planet. There is good reason too. Which you will soon see.

You will be very pleased I am sure.

73 Jeremy

--- On Sun, 3/20/11, Bruce Junkin <ki...@msn.com> wrote:

> > Good luck.  It’s my understanding the
> transistors aren’t made any more. Let us know how it works