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Author Topic: TS-430S - Smoked (literally) Finals?  (Read 10287 times)
KD5FHW
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« on: March 17, 2012, 10:58:47 PM »

So I was making some contacts with my brother-in-law's good ol' TS-430S that we picked up at a hamfest last year. Radio worked great after a tune-up and AM install. It even had elderly relays that suddenly were reinvigorated and worked fine. Well, I'm transmitting AM on the DX portion of 160m so his LDG Z11 Pro 2 tuner could get a decent tune and after about 15 seconds I see smoke coming from the rear of the radio.

I'm sure it's the finals, but my question is, can they be replaced in 2012?

I'm going to take it to the local ham shop, Houston Amateur Radio Supply, on Monday to see what Russell says, but I thought I'd ask the knowledgeable assemblage here on eHam.
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ZS5WC
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« Reply #1 on: March 17, 2012, 11:49:05 PM »

Hi Andrew,

Sorry to hear about your misfortune.
The TS-430s is a great rig--with some issues, but I love them so much I have no less than 4 of them!..

What power output were you using to tune--5 watts should be sufficient, and 100w solid CW /AM carrier is absolute taboo!. The AM capability of this rig is about 25w, but then you are already border line.
Regarding the smoke--the SWR protection should have limited the output whilst the tuner is trying to tune--so perhaps the pots have been 'TWIDDLED'. Secondly I don't think finals will SMOKE?--I think they will just blow. So possibly you have lost your driver transistors, and the two 15ohm bias resistors on the driver bases.
If the drivers are blown, before re-installing new ones , make sure the bias control pots are clean and the bias regulator transistors are working ok. I have had the bias transistor fail before, and blow the drivers.
Take note the driver pinout is strange--not the usual BCE I recall it is CBE, and I used 2SC1969's for drivers, but had to swop the transistor pins.
A good final substitution is MRF454 or EGC / NTE 335.
The final bias adjustment in the manual is a bit lacking--a simple way is to reduce both bias pots anti clockwise, mA meter in + leg to rig, SSB selected , engage MOX without any speech,
Increase driver bias very carefully to add 250mA to the existing mA reading in transmit.  Then add 250mA to 300mA final bias.
If your are not too sure, get a good radio tech to do this for you-as those transistors blow very easily!.

73 de William
ZS4L
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W8JX
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« Reply #2 on: March 18, 2012, 05:21:06 AM »

Well, I'm transmitting AM on the DX portion of 160m so his LDG Z11 Pro 2 tuner could get a decent tune and after about 15 seconds I see smoke coming from the rear of the radio.

You should never tune in AM mode. Rigs duty cycle and safe power output capability is greatly reduced in AM mode. Always tune in CW mode and reduced power. 
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N4NYY
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« Reply #3 on: March 18, 2012, 06:47:31 AM »

You are going to have to open it up and stick your nose in there. Usually, you can see the offending component.
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K0OD
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« Reply #4 on: March 18, 2012, 06:52:40 AM »


Quote
Radio worked great after a tune-up and AM install.

I still have mine, a delightfully simple radio to operate. Yes, the bandpass filter relays are finicky. It was a low-end radio that shouldn't be pushed, especially after almost 30 years.

The TS-430 came from the factory with very limited AM capability. What exactly is the "AM install" you installed?

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KA5IPF
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« Reply #5 on: March 18, 2012, 08:04:46 AM »

What is limited about the AM in the 430? It does 100w PEP same as SSB & CW.
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N4NYY
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« Reply #6 on: March 18, 2012, 08:55:04 AM »

Quote
What is limited about the AM in the 430? It does 100w PEP same as SSB & CW.

I think most of the solid state rigs are optimized for SSB. I think the modulation for AM is set around 70% or so. For example, I do still use a CB (restored TRC-455). When I have heard solid state ham rigs on the air, like Icoms or Kenwoods, they sound like total crap. They sound like you have 5 socks over the mic. Yet when I hear a tube rig like an old CB or an FT-101, they sound simply fantastic. I guess that is why the AMers on 75M use old 1950s and 1960's rig.
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KE3WD
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« Reply #7 on: March 18, 2012, 09:57:10 AM »

Quote
What is limited about the AM in the 430? It does 100w PEP same as SSB & CW.

I think most of the solid state rigs are optimized for SSB. I think the modulation for AM is set around 70% or so. For example, I do still use a CB (restored TRC-455). When I have heard solid state ham rigs on the air, like Icoms or Kenwoods, they sound like total crap. They sound like you have 5 socks over the mic. Yet when I hear a tube rig like an old CB or an FT-101, they sound simply fantastic. I guess that is why the AMers on 75M use old 1950s and 1960's rig.

You are listening to operators who do not know what they are doing, likely the "all knobs to the right" attitude is in there as well. 

The informed operator with knowledge will back off the RF gain of the Carrier to get the modulation to match with the solid state rig.  I've proven this over and over again, with many different rigs, mics and antennas, often able to get signal reports that are very favorable, even from the old all-boat anchor high level modulation guys and gals.  Some of them have refused to believe the rig report sometimes, for even they fall prey to this "common knowledge/urban rumor" problem. 

Far too many do not understand the relationship between that Carrier and the all-important AM sidebands.  Backing off the Carrier Insertion allows a proper ratio between Carrier and Sidebands.  A peak reading wattmeter is handy, but not mandatory here.  One can also adjust that RF Carrier level properly thru use of signal reports. 


73
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AC5UP
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« Reply #8 on: March 18, 2012, 10:09:18 AM »

I guess that is why the AMers on 75M use old 1950s and 1960's rig.

I'd guess it's more a case of geezers using what they know best and picked up cheap 30 years ago........ I could be wrong in some cases, and you'll find there are still Hams who experiment and homebrew with Ancient Mary: http://www.classeradio.com/

As for the notion of a Kenyaecom sounding bad on AM... Yes... I know from personal experience that an IC-756 will sound nasty in AM  *IF*  the SSB speech proc is left turned on. Best guess is the factory assumed the chances of someone running AM were slim and didn't think to auto-disable it with the mode switch, but when the processor is turned OFF the radio will get exceptionally good audio reports. AM is not as plug & play as SSB and to get the best from it does require some smarts on the part of the operator. That's where it goes wrong..... And in some cases, terribly, horribly, (the only way this could get any worse is if we moved to New Jersey) wrong...

BTW: If you add up the total RF power in two sidebands plus carrier, a "40 watt" AM signal is about the same as 100 watts PEP / SSB. KE3WD is correct that in some cases you match the modulation level to the carrier, in other cases you adjust the carrier level to the audio. No matter how you balance the two they still need to be balanced......... 15 seconds in AM at 100 watts for antenna tuning shouldn't smoke anything.
« Last Edit: March 18, 2012, 10:22:51 AM by AC5UP » Logged

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W8JX
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« Reply #9 on: March 18, 2012, 10:12:20 AM »

What is limited about the AM in the 430? It does 100w PEP same as SSB & CW.

Limited to 25watts zero modulation carrier.
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AD6KA
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« Reply #10 on: March 18, 2012, 03:44:36 PM »

I hope your 430 isn't too expensive to fix.
I had one for a long time and loved it.
Simple to operate and build like a brick sh**house.

I have kicked myself a thousand times for
selling it in a moment of sympathy for a
newly minted ham. I hope he got good use
out of the old girl.....

73, Ken  AD6KA
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KD5FHW
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« Reply #11 on: March 18, 2012, 03:47:28 PM »

Thanks for the input guys. When I take it in tomorrow I'll be armed with some info.

As for the "AM install", I forgot to add the word "filter".  Grin
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KA5IPF
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« Reply #12 on: March 18, 2012, 04:09:16 PM »

What is limited about the AM in the 430? It does 100w PEP same as SSB & CW.

Limited to 25watts zero modulation carrier.

In that case your SSB rig is worse off, zero carrier with zero modulation.

25 watts of carrier at 100% modulation equals 100w PEP. Look it up.

Clif
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W8JX
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« Reply #13 on: March 18, 2012, 04:32:25 PM »

What is limited about the AM in the 430? It does 100w PEP same as SSB & CW.

Limited to 25watts zero modulation carrier.

In that case your SSB rig is worse off, zero carrier with zero modulation.

25 watts of carrier at 100% modulation equals 100w PEP. Look it up.

Clif

That is why they are limited to 25 watts carrier.
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ZS5WC
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« Reply #14 on: March 18, 2012, 11:40:54 PM »

 Smiley

Let us know what you find?..
I forgot to mention , when removing the PA--do not remove the PA screws on the back panel, remove the complete back panel screws, CAREFULLY tilt over the back panel and remove the PA assembly RF shield. Then remove all the plugs, and desolder the supply wires to the PA.
Do not try and extricate the pa assy. through the back panel!.
Also beware all the cables are VERY short--when the panel is tilted over carefully remove them and make a note of which plugs go where.

Amazing how the AM discussion started out of this--I must say I also still prefer proper Plate modulated AM!.. (Sorry off topic I know..)

73 de William
ZS4L / ST1
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