HTX-202 Problem

FN04 · Post by **FN04** » Sun May 24, 2009 2:16 am

Hi all I picked up a clean HTX-202 at a local yard sale for $2.00. It needed an antenna. So i supplied one for it.

Here is the issue after testing it out I discovered it will not transmit below 145.000 MHZ. Above that is fine. When below 145 and you press the PTT the radio transmits for a split second and then stops.

Any help would be great. thanks

wx1f · Post by **wx1f** » Sun May 24, 2009 8:53 pm

FN04 wrote:Hi all I picked up a clean HTX-202 at a local yard sale for $2.00. It needed an antenna. So i supplied one for it.

Here is the issue after testing it out I discovered it will not transmit below 145.000 MHZ. Above that is fine. When below 145 and you press the PTT the radio transmits for a split second and then stops. Any help would be great. thanks

The PLL is out of alignment. Either the crystal is bad or the last person to own it, got into the circuitry and diddled with the pll can. Sell it for parts. I'll bet someone will help you double your money. I don't know any shop that repairs them anymore. And those that say they do are only resoldering joints...not actually replacing anything but the internal battery..and charging you $45 an hour labor, fixed or not!!.

FN04 · Post by **FN04** » Mon May 25, 2009 1:23 am

thanks I was kind of hoping it would be an easy fix to get it working again. Just seamed strange how it would transmit above 145 no problem. Just figures the best local repeater is 145.350 (144.750 input)

Mike Alexander · Post by **Mike Alexander** » Sat May 30, 2009 9:27 pm

A quick test, while pressing PTT on 144.200mhz check the voltage on the Test Point on the VCO Can, should be 1.8 to 2 vdc. If not adjust TC201 (adjustment nearest bottom of radio on vco can) and see if it will come into spec. 73
Mike n0bxe

FN04 · Post by **FN04** » Sun May 31, 2009 2:09 am

Thanks Mike I will have a look at the schematic and see if I can find those points.

FN04 · Post by **FN04** » Sun May 31, 2009 3:03 am

Mike Thanks for the tip. I looked at the diagram and my eye went fuzzy. If you have worked on a 202 before could you point out the test points and pot? I can supply a pic of the radio opened up. thanks

Mike Alexander · Post by **Mike Alexander** » Sun May 31, 2009 4:53 pm

On the RF board the vco is a metal can at the bottom of the board. The test point hole is on the left side of the can, the two adj holes are on the right side. The hole nearest the top of the can is the rx vco adj (L202). The hole nearest the bottom of the can is the tx vco adj (TC201). Do not adj the controls outside of the can, those are modulation and freq adj. There is most likely a free service manual out on the web with pictures to make it more friendly. Hope this helps. Nothing much more fun than making a garage sale item work. 73
Mike n0bxe

FN04 · Post by **FN04** » Sun May 31, 2009 8:09 pm

Thanks that helps a lot. I got a manual on-line. I will give it a go. I assume the test points are TP and ground or is it +. Thanks john

FN04 · Post by **FN04** » Sun May 31, 2009 9:49 pm

any tips on how to check this. The RF is sending my digital meter into a fit.

Mike Alexander · Post by **Mike Alexander** » Sun May 31, 2009 10:05 pm

I've never had that problem...if it's tx rf than you are winning the battle because the vco must be locked. Make sure the radio is in low power mode and maybe try something like a .01uf cap across your meter leads. The vco case is gnd and the tp is +.

Mike Alexander · Post by **Mike Alexander** » Sun May 31, 2009 10:09 pm

oh....use a dummy load instead of your antenna also may help.
Mike n0bxe

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