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Old 1st Mar 2023, 3:58 am   #1
nemo1956
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Default Trio Kenwood,TS-510 poor receive.

Hi guys.
I have got my old TS-510 out after a very long retirement.
I brought it up on a Variac and there seems to be two things that is not working.

1:Very poor receive. It's not too bad at 3.5MHz but as you go up in bands it gets weaker.

2:It will only recieve on USB. Both LSB and CW has no output again on receive.

Not tied transmit yet, but as I'm only going to use it for receive I may not bother with that part.

Mind you there are no 6146's or driver valves in it.

Can anyone help me with this?

Thanks, Paul G0MIH HS0ZLQ.
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Old 1st Mar 2023, 8:44 pm   #2
frsimen
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Default Re: Trio Kenwood,TS-510 poor receive.

Hello Paul,

The LSB and CW modes share the same crystal oscillator on receive - they share the same crystal too, unless you have the optional crystal filter fitted. If the crystal oscillator isn't running, there won't be any reception, so I suggest you have a good look around Q001 on the UC1405J board. You could swap the LSB and USB crystals to see if the problem transfers with the crystal.

Paula
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Old 2nd Mar 2023, 12:56 pm   #3
nemo1956
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Default Re: Trio Kenwood,TS-510 poor receive.

Hi there Paula.
Yes I can see that on the schematic.
I have measured the voltages on both Q1 abd Q2 and they are both the same.
I did suspect that the two crystals had gone tits up but I took the working one out then put the CW one abd it worked.
Mmmmmm.
I've also measured the resistors from one side to the other and they all read the same too.
I may take out Q2 and replace it with BC547 ans if it's the gain of the 2SC373 has gone off?
Any more thoughts.
73's
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Old 2nd Mar 2023, 1:50 pm   #4
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Default Re: Trio Kenwood,TS-510 poor receive.

I'm afraid I've come across a number of Japanese transceivers of this era where crystals have failed.

You can check them with a signal generator and oscilloscope orRF voltmeter.

David
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Old 2nd Mar 2023, 2:07 pm   #5
Cruisin Marine
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Default Re: Trio Kenwood,TS-510 poor receive.

Quote:
Originally Posted by nemo1956 View Post
Hi there Paula.

I did suspect that the two crystals had gone tits up but I took the working one out then put the CW one abd it worked.
Mmmmmm.

Any more thoughts.
73's
Look at post number 27 and others https://www.vintage-radio.net/forum/...=186860&page=2

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Last edited by Cruisin Marine; 2nd Mar 2023 at 2:16 pm.
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Old 2nd Mar 2023, 2:24 pm   #6
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Default Re: Trio Kenwood,TS-510 poor receive.

He's been logged in this morning.

So I assumed busy.

Cheers

Mike T
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Old 2nd Mar 2023, 2:35 pm   #7
Cruisin Marine
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Default Re: Trio Kenwood,TS-510 poor receive.

Oh good, as long as he is ok.
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Old 6th Mar 2023, 1:07 pm   #8
nemo1956
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Default Re: Trio Kenwood,TS-510 poor receive.

Hi guys. Latest on the problem.
I removed all three crystals and placed them into the working g oscillator. They all seem to work.
I put them back in one by one and now both USB and USB is working but the CW will run with no crystal installed into it.
I think there is a short somewhere or a problem with the circuit board itself.
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Old 6th Mar 2023, 2:52 pm   #9
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Default Re: Trio Kenwood,TS-510 poor receive.

Is that just testing RX? Isn't it common that CW uses the same RX crystal usually but not always USB. The CW crystal is selected on TX only.
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Old 6th Mar 2023, 6:31 pm   #10
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Default Re: Trio Kenwood,TS-510 poor receive.

It sounds like you haven't cut the link between the CW and LSB crystals. See the attachment for more information. Having two crystals in parallel would stop either from working too, in all probability.

Paula
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Old 7th Mar 2023, 10:33 am   #11
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Default Re: Trio Kenwood,TS-510 poor receive.

The TS520S Manual I have downloaded shows 4 crystals. USB, LSB (both used TX & RX) For CW there is RX and TX spaced by 700Hz the expected wanted beat note.

Paula, your attachment looks like a modification sheet to convert from 3 crystals to 4 for more convenient CW tuning. CW was using the LSB RX crystal on RX. I can't find that in my manual.

Last edited by Jon_G4MDC; 7th Mar 2023 at 10:44 am.
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Old 7th Mar 2023, 4:07 pm   #12
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Default Re: Trio Kenwood,TS-510 poor receive.

Jon

Its on p20 under installing the CW crystal filter

Fred

Quote:
Originally Posted by Jon_G4MDC View Post
The TS520S Manual I have downloaded shows 4 crystals. USB, LSB (both used TX & RX) For CW there is RX and TX spaced by 700Hz the expected wanted beat note.

Paula, your attachment looks like a modification sheet to convert from 3 crystals to 4 for more convenient CW tuning. CW was using the LSB RX crystal on RX. I can't find that in my manual.
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Old 7th Mar 2023, 5:29 pm   #13
frsimen
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Default Re: Trio Kenwood,TS-510 poor receive.

Jon,

The TS520S is a mostly solid state transceiver with three valves. The TS510 is a much older design, mostly valved. As Fred stated, the circuit extract is from page 20 of the TS510 manual.

Paula
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Old 7th Mar 2023, 7:17 pm   #14
Jon_G4MDC
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Default Re: Trio Kenwood,TS-510 poor receive.

Yes, thanks Paula and Fred. You are right that I was looking at the later set.
Lucky that they are so close that the HET OSC circuits are almost the same.

In the 520 you got the 4th crystal which was an option in the 510. Hope the OP can sort it out with your extra information.
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Old 22nd Mar 2023, 1:28 pm   #15
nemo1956
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Default Re: Trio Kenwood,TS-510 poor receive.

Cutting the link is only done when you fit the extra CW filter.

I took all the crystals out of the board and and tested them.
One worked the other two did not.
But after trying them several times they doth started working.
I put them back into the board and they still work.
So I'm guessing that the needed waking up after all these years of not operating.
Next problem is that it's very deff at 28mhz.
Ive tested the valves and they are not to bad. I then did a tune up of the coil pack. That mad a small difference but not much.
Am I looking at a fault or is this radio I herently deff at 28mhz?
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Old 23rd Mar 2023, 9:46 am   #16
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Default Re: Trio Kenwood,TS-510 poor receive.

Seeing how the TS510 RX path works I would suspect low Local Oscillator level.

See V201, Q201 and the drive to V203.

The 10m crystals are all in the 36MHz range. By contrast 15m is about 30MHz and other bands much lower. I suspect your LO runs out of steam.

That might be less critical on TX. On RX they needed to add a transistor buffer.... why?

Last edited by Jon_G4MDC; 23rd Mar 2023 at 9:56 am.
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Old 1st Apr 2023, 12:45 pm   #17
nemo1956
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Default Re: Trio Kenwood,TS-510 poor receive.

Hi there. Thanks for your help.
It seems like there is some intermittent problem as now when I swith it on it all works but after about 20 minutes it will stop working. No mater what I do it will now work again u less I turn it off and leave it for an hour or two.
The second problem is its very deff on the higher bands.
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Old 1st Apr 2023, 12:55 pm   #18
unitelex
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Default Re: Trio Kenwood,TS-510 poor receive.

I'd be checking for dry joints particularly around any sockets connectors
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Old 20th Apr 2023, 11:27 am   #19
nemo1956
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Default Re: Trio Kenwood,TS-510 poor receive.

Hi there. Yes I think you are correct with the local OSC levels but I can find any information on what the levels should be.
Do you have any information on this.

Many thanks.

Paul.
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