• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

HTX-10 freq expansion with resistor?


Nov 18, 2009
Anyone successfully done this mod?

HTX 10 MOD 25.150-29699mhz 1.open radio look up on front face board if you look very carefully you will see 2 solder pads where there could of been 2 pins for a jumper plug (like the 2950's)you will see one side goes to a smd. and the other goes to a ground island solder a resistor 10 ohms across pads (the resistor is brown black black gold 1/4 watt) Now put the radio back together and hold fun' and button 2 in while turning on .the radio will have a 40 channel display on right of freq display 1-40 press 2 to change bands along w/ lower left button' THERE is NO fine mod for radio due to missing components. and you know how to turn up amc and alc in the rear. 88's
KB2LJJ Radio Mods Database and Manuals

Thats the only place i have seen this mod published. Its not on mods.dk, nor defpom except a link on thier forums to same.
Some people say it uses a different chip than its cousins like the Magnum, cannot be modified for expanded coverage, except KB2LJJ mod.
Is this mod total b.s., does it work with early production models or all of them?

I have read that the only way to mod an HTX-10 is to change the cpu because Radio Shack had it purposely manufactured to not be able to mod it. There is no "channelized " programming in the chip like there is in the 257 and like clones.
Yes, Ratshack has had that policy for some time now, still doesnt mean it cant be done. The FCC has a similar policy for manufactures not on their good list, especially radios approved for class C CB. Many radios over the years have been taken out of production, reengineered or just had the chip coated in glue to keep them happy.

I posted this in the hopes that I will find someone who done it with success or done it and failed, and if so how bad it failed.

For all I know QRZ hams made this up so people would ruin their radios.

I posted this in the hopes that I will find someone who done it with success or done it and failed, and if so how bad it failed.

For all I know QRZ hams made this up so people would ruin their radios.

Bastards.....all of them
  • Like
Reactions: 870Arizona
Yep, and wost part is, even if there is someone on here who done tried this mod, and it toasted their radio............Would they admit they done it?
  • Like
Reactions: rabbiporkchop
uses the same chip only with different program, LC72322 by sanyo, fairly common chip, capable of up to 150mhz operation.

Problem is, the software permanently encoded on the prom, "sys 205" limits chip to 28-29.7mhz.

If only I could find a supplier of this chip in small quantities.

Its a little out of my league but I have friends who could reverse engineer the sys 204 (magnum 257) chip and upload the data into a file to be copied, then its just a matter of blowing the data to the new (bootleg) LC72322 chips.

of course it takes quite a setup and skill to solder a 80 pin smd. With the magnum and its cousins going for $200-$250, screwit I will just get a 257 unless someone finds a crate of LC72322 chips with system 204 burnt into them collecting dust in the back of some warehouse somewhere.
  • Like
Reactions: Pez
its the same chip, same pinouts, only it seems some of the pins on the HTX arent used compared to the 257.

e.g. band up, band down, cb, etc. http://www.cbtricks.com/radios/rflimited/magnum_257/graphics/magnum_257_sch.pdf

This conversion has been done before, or so quite a few others are saying.

As for soldering SMD, there are ways. I would likely use the solder paste method and cover with epoxy but there may be a better way. More and more people are developing work arounds and techniques for SMD devices.

I would love to have a couple of chips to play around with but they need to say "sys 204".

I dont even own an HTX-10, I just see it selling for under $100 on ebay less on craigslist.
I have the HTX-10, TRC-485, & 257.
Having these similar radios, I opened them up & compared notes. All 3 are quite different. The 257 was an easy frequency mod. The 485 took some time to figure out but I added a momentary micro push switch on the side and it works like the 257 with band lettering display. I wanted to see if a mod for the 10 was possible for giggles. I do have to say that it's an awesome 10 meter rig and works great. So I found the resistor mod mentioned & figured I would try it.
First, locating those pads that look like something was there is very hard to do but having the 257 made it easier to find what they meant. I did what the mod said to do w/resistor and then powered up. All I got was the backlight on but no display. I rechecked where everything was supposed to go and got the same thing. I removed the resistor & everything is back to normal with no harm done. I spent quite a few hours looking it over and found unless the chip is changed there is no quick mod. I enjoy the radio as it is and have the others to compliment operating needs. So, no, it doesn't work at all.
I have a friend with 2 of these IN THE BOXES BRAND NEW he was also thinking there was a mod but he 2 found out otherwise. I been thinking about buying them for mobile 10 meter radios for my licensed son and daughter. If I remember correctly e wanted $150.00 for the pair of them. I bought 2 dual band HT radios in the boxes from him 2 years ago HTX 245 I believe they are and they are nice radios.

Help Users
  • No one is chatting at the moment.
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.
  • dxBot:
    kennyjames 0151 has left the room.