Author Topic: HTX-100 repair  (Read 354 times)

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Offline WB2SVF

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HTX-100 repair
« on: February 06, 2020, 01:22:38 PM »
I have an HTX-100 that needs some repair and I need some guidance... my only repair experience is on things that use tubes and weigh 50 lbs... if it has ICs, I simply have become an appliance user.

I was forced to take down my station 10-12 years ago - - this radio has been in storage in my house since then with no temperature extremes.  I am the original owner and it was working when I put it into its box.  I am now setting everything back up.  When I apply power, the display light lights but there is no information... no frequency, no nuthin'.  There is audio, but there is no static sound when I connect the antenna.

My first thought is: bad capacitor.  I pulled off the cover and looked at both sides of the main boards with a flashlight and magnifier... none of the capacitors had an indication of having split or burned, and there was no trace of leakage on the solder side of the boards.  I do not have a full schematic or a shop manual, so I don't know where to turn next.

I watched Buddy's repair YouTube where he brought back to life an HTX-100 and checked what he did in that radio, but I do not think I have that problem... 

Offline The Radio Shop

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Re: HTX-100 repair
« Reply #1 on: February 06, 2020, 02:16:59 PM »
First welcome to the site.

This sounds like a known issue with the radio in question.
Have a good look at the PLL board.  It is the smaller board sitting in the can that is attached to the chassis on one side.
You will need to unplug this board and remove it from the mount. Look closely for weak solder joints. They are there.
Also look for Sony Bond glue. This is a beige color glue that was used to hold parts down.  It has probably turned dark brown by now.
This stuff is very conductive and causes shorts.

I understand what you said about the capacitors.  But to be really sure you have to remove them and see if they leaked onto the board.

You can get the service manual here:
http://www.cbradio.nl/realistic/Service_Manual_Realistic_HTX100_Homer_ENG.pdf

Let us know what you find.

Buddy
Buddy kc4umo

Offline WB2SVF

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Re: HTX-100 repair
« Reply #2 on: February 06, 2020, 05:46:20 PM »
Thanks for that guidance.  I took the PLL board out and removed it from the can so I could examine the foil side.  I checked every square inch of that board with my focusing loupe (...I do large format photography, too...) and a flashlight and I could find no weak or cold solder joints.

Not on the PLL board but on the main board, there is a lot of that glue that is blobbed onto the base of some of the components that has turned brown.  Should I chip away at it with a small jewelers screwdriver?  Or is there something that I can use on a Q-tip that would dissolve it?

I'm wondering if the PLL might be OK, but there may be some signal from the PLL that is being shunted to ground because of that glue?

If I am not successful finding the problem, do you still repair these radios?  To be honest, I no longer have any test equipment other than my VOM...  so I'm not sure how much diagnosis I can do other than look for shorted or open components and check for voltage at specific points.  I just boxed up my TS-850SAT to send out for repair (similar symptoms, actually...) and thought I would get the 10M HTX-100 going while the 850 is away... LOL  All that's left is to try my homebrew 20M QRP rig.

Thanks, again for your guidance.  And I have really enjoyed watching your videos.  I wish YouTube had been a thing back when I was active the last time.

Wes, WB2SVF