Trio TS700G.
 

Split from this thread:-

https://www.vintage-radio.net/forum/...d.php?t=155987

Does it have one of the Mitsubishi power amp modules?

They can crack their ceramic substrate inside the plastic cover and the fractured tracks and spiral inductors often make contact when cold, making the power drop when hot.

Oh, and welcome!

David GM4ZNX

Re: Trio TS700G
 

Hi, I can't see anything fitting the description. What area of the radio would I look for that?
I ought to explain that I'm new to the electronics hobby. I'm currently studying towards my full amateur license which is one of the reasons I wanted to fix up an old radio and thus, I have a basic understanding but this is all very new and heavy stuff for me.

At the moment I'm struggling to find the second relay of 2!

Cheers
2E0VZZ

Re: Trio TS700G
 

TS700 (no letter)

http://www.rigpix.com/kenwood/ts700_manual.pdf

TS700A (US model) probably quite similar?

http://www.repeater-builder.com/kenw...700-op-man.pdf

Service manual

http://www.k9rod.net/TS-700-SM.pdf

Previous thread with some offers of manual copies (and one dead link on post 18)

https://www.vintage-radio.net/forum/...ad.php?t=29922

73 Fred
G4BWP

Re: Trio TS700G
 

Hi Fred, Greatly appreciate your time and efforts there, thanks.
All printed out and the fun is ongoing.
I've discovered they used a technique in the olden days of wrapping wires around pins. This is going to cause me problems as a lot of them have since been soldered over, presumably to improve the integrity of the connection.

I'm thinking I may do well to cut all the wires in the middle of the runs and fit some form of micro bullet connectors so the boards are removable now and in the future. I bet I'm not the first to do this...

Lots to learn here.
73's
2E0VZZ

Re: Trio TS700G.
 

They'll likely have been soldered 'cos they've been off before. Wirewrap joints per se are pretty reliable, first time round :-)

I'd be wary of adding connectors in any signal carrying lines, though if there's room and the spacing fits maybe replace the pins with a suitable header and terminate the lines with a matching connector. Gold plated if you can find/afford.

Re: Trio TS700G.
 

I wonder what this addition is, it connects on one side of the resistor to a pin on the repeater mode selector, the other side goes to a pin on the HET unit. Ive googled ASTRALUX and the text on the can but found noting.

Ive not dug any deeper yet to see exactly where the wires are going but I wonder if it would be sensible to remove this addition first prior to working through the rest of the radio.

Opinions gratefully received on removing it first and what it is?

Cheers
2E0VZZ

Re: Trio TS700G.
 

Thanks for that. A good idea with the headers. The pins are long with up to 3 wire wrap joints on some. Ill have a look at the options but I think a removable solution is probably the way to go.

Cheers
2E0VZZ

Re: Trio TS700G.
 

Looks like a filter?I was going to say RF pre amp as they can sometimes help these sets ,though I think looking I am wrong.
Great rig,I have the same model I bought new years ago.Needing to put up my Diamond vertical at present.

Welcome to our excellent group!

Re: Trio TS700G.
 

Thanks for the warm welcome, Im very pleased to have made contact with an owner of the same radio. We may be able to assist each other in time.

I also think it is a filter after looking at other filters but I don't know why it is there.

Ive had a few QSO's through this rig already but its performance deteriorates rather quickly. when its working, the audio both ways is fine, when it warms up, it deteriorates dramatically. A slap will sometimes bring it back but not always. I also had the issue of the output power dropping to zero gradually on TX. This was partially cured by taking the big relay out and cleaning the contacts but it still does it sometimes. Im searching out the other relay but haven't found it yet!

I use a Diamond X50 at home, at just 30M ASL I can access 7 analogue repeaters (70cm included) and can work right down into South Yorkshire. I also use a 5 element Yagi on a clark mast on SSB and have made it to Montrose in Angus from Thirsk on 10W so I hope to be able to do the same with the 700G

Cheers
2E0VZZ

Re: Trio TS700G.
 

Not been in mine apart from fit a homebrew RF pre amp again many years ago.The relay could be hidden under a panel somewhere.
Tapping other than Relays being intermittent very often is the infamous dry joints.

Re: Trio TS700G.
 

Ah, good, it doesn't have a module in the RF power amp, it's good old discrete transistors.

I suspect you're on a hunt for a bad soldered joint on a board or else an iffy component. A can of freezer spray may have a part to play in your future!

David

Re: Trio TS700G.
 

A common fault is low Tx power caused by failure of the DC-DC converter used to
generate 21 volts dc for the rf power amplifier.

I found this useful;
http://www.radiomods.co.nz/kenwood/kenwoodts700.html

Re: Trio TS700G.
 

The Astralux component on the Veroboard may well be a RELAY.

Re: Trio TS700G.
 

An update.
Ive spent a few hours so far on this and yesterday I had a cracking series of QSO's through it. So much so that I was beginning to think it was fixed.
The antenna changeover relay is a metal box and appears to be working well.

Then, after switching off and back on I have nothing at all in TX and RX. Its deaf and mute.

Where would you look?

Cheers
2E0VZZ

Re: Trio TS700G.
 

It's the power supply, only 3 volts out where I need 9 and 14 out where I need 20
That explains a lot of the issues I was having before it failed.

2E0VZZ

Re: Trio TS700G.
 

Now repaired with and I used the radio in the UKAC 2m contest this week.
Works a treat.
2E0VZZ

Re: Trio TS700G.
 

What was the cure?

Re: Trio TS700G.
 

Did a few things, most notably I enlisted the help of a ham that is also an electronics expert. He removed the old components that were causing the problems and installed fewer, modern bits in their place. Now works wonders.

I also removed the transformer which can be refitted later and made the PSU a plug in system for the future as its only getting older and will no doubt have to come out again in the future.

Re: Trio TS700G.
 

Great job,hope mine keeps going when I get it back in regular use.

Re: Trio TS700G.
 

Thanks, I'm sure yours will last forever, this one has been my only radio for the last week or so as I'm testing it extensively. I've just received its next upgrade in the post. Ill fit this ASAP, its a CTCSS generator.

2E0VZZ