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Search results

  1. MKwrench

    Audio has to pump up?

    I guess it was too big, I had no idea that could happen. It must have been like that for a while, I don't know why I didn't notice before... I tried a 2.2uf and a 1uf (which I thought was there), they both caused simular delays.
  2. MKwrench

    Audio has to pump up?

    I wasn't going to have time until tomorrow morning, but plans change. I was exited to try Brandons suggestion of pre heating some of the 1156s nearby components. Before I grabbed the soldering iron, I wanted to look if any DC voltages on any of the pins changed during the "pump up", which could...
  3. MKwrench

    Uniden pc122xl no tx or rx

    I did this on a hunch with a simular radio. Find test point 2 and measure voltage to board ground/ not chassis ground, on channels 1 and 40. Remember the number on 40, while keying slowly turn L13 to its max top and bottom while watching your watt meter for movement. record max and min...
  4. MKwrench

    Audio has to pump up?

    I have fun posting these, I always hope someone can learn along with me, and maybe geta kick out of seeing these old radios come back to life. Here's another Sears Roadtalker, it's a 663.38070700 AM Radio. I had recently pulled a few radios off the shelf to make sure they work to put on...
  5. MKwrench

    Uniden pc122xl no tx or rx

    Is the VCO voltage in check? It might just be out of lock. I think a failing channel switch can do this also by creating incorrect pin combinations. I feel we should hear a small POP when the power switch is cycled, so be prepaired for multiple issues. (or do they fully mute, out of lock?) I...
  6. MKwrench

    Bummed that my Roadtalkers Xtal is out of whack

    Theres a Neon Bulb with a 150pf in parallel before the SWR bridge. Does anyone know what thats about? .... A safety device maybe?....
  7. MKwrench

    Bummed that my Roadtalkers Xtal is out of whack

    This Roadtalker is back on the shelf until I feel more capable of verifying the integrity, bandwidth and center of the filter. Otherwise if a parts radio comes along I'm just going to Hail Mary it with the suspected goods. The adjustments behaved in a simular way in one of my 2-button...
  8. MKwrench

    Bummed that my Roadtalkers Xtal is out of whack

    I'm going to try monitoring while removing the probe. Just a satisfy that part of my curiosity. I did try to monitor at different spots too. I might button this one up until I get a parts radio or a VNA to put my mind at ease. Anyway I found that If anyone wants to pump up that modulation...
  9. MKwrench

    Bummed that my Roadtalkers Xtal is out of whack

    Thanks for getting back with me, I don't not have a VNA or a spectrum analyzer that I could do this with. If I did it would be my first time trying a sweep on a filter. These are tools that are next in line to treat myself with.
  10. MKwrench

    Bummed that my Roadtalkers Xtal is out of whack

    It's a 934.38270700 "Slantface Roadtalker 40. I've wanted one of these for a while, so when one popped up for peanuts I had to grab it. AM worked alright but showed only about 75% Modulation on a 3 watt carrier. Transmitting on the upper sideband sounded close to being in tune , but real bright...
  11. MKwrench

    Has anyone figured out a night watch solution on lighting?

    https://www.westcoastmall.net/380051.html I ordered new faceplate/bezels from here a few times, I believe they used to be under $20. Check if you have AC voltage supplied from the lighting module at the ribbon connector (it might read as high as 90v), if so a new face will fix it. Otherwise...
  12. MKwrench

    11 meter is very quiet?

    3/16/26. Very weak today, I normally hear Europe and good chunk of what's around, in the morning. But nothing today ☹️, just "falling water" with bits of pepper in it.
  13. MKwrench

    399 JJ - Mods-for-Upd858-Chassis

    Theres a similar page on the 010 chassis by 399, floating around out there too. https://senorjj399.wixsite.com/the-pb-010-chassis Not trying to steer off topic. He was relly cool for sharing his documented notes with the world.
  14. MKwrench

    399 JJ - Mods-for-Upd858-Chassis

    The 449 is the same. As an experiment, I changed C69 to 1uf tant, C77 & C78 to .47uf, C87 to 10uf, and R220 (in the D23 spot) to a 1N4148 diode. That should open things up a little, but it's hard to tell if its all in my head or not on my monitor radio. On air, I get reports of great sounding...
  15. MKwrench

    Old uniden Grant PC409ac board

    C18 helps keep the 8v line for the limiter and part of the mic line steady, sometimes the original value cant handle the switching of the transistors in that area, causing clicking or squealing noise. Ive read somewhere that bumping it up to a 330uf to 1000uf fixes all kinds of mic issues. I had...
  16. MKwrench

    Old uniden Grant PC409ac board

    The 1137 should be fine, The AM regulator can be upgraded to handle more amperage, the same way a 148GTL would be. I don't remember the "popular TIP" part numbers offhand but I think one or two of mine have a "D44H11" In the a.m. regulator spot. It's just a 10 amp transistor, to allow a little...
  17. MKwrench

    Old uniden Grant PC409ac board

    I had 2 that did this. On one I noticed that dropping the bias on the driver helped a little, but made sideband crunchy. It was TR41, changing the AM regulator fixed it. On the other it ended up being the driver itself I used an HG branded 2166, use the scope and your ears to set the bias on...
  18. MKwrench

    Uniden pc68xl help

    On a PC66, VR4 will be VR5, L14 will be L10. I think the 68 is the same.
  19. MKwrench

    Uniden pc68xl help

    To add to my last post: Setting the deadkey through the amp into a scope to get 100 to 125% growth (after amp) is what I found to be the sweet spot between "Loud Enough" and "Kazoo". It will be way more from the bare radio, swinging 18 watts from 0.5 will distort the receiving radio, but...
  20. MKwrench

    Uniden pc68xl help

    For a clean swing, remove R44, then solder the anode of a 1N4148 or 1N400(#) to JV17 and the cathode (stripe side) to the positive side of a 10uf (25v+) electrolytic cap, ground the negitive side. Install 1 of the bottom legs of a 1k (102) VR into the R44 hole closest to C49 and the top leg to...