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  1. MKwrench

    858 PLL Mods and stuff

    I started on a TRC449 today and was looking for 858 info. This post popped up. Here's something I saved a while back. If it's not allowed let me know, I'll take it down.
  2. MKwrench

    Cobra 29LTD/GTL 10 KC mod????????

    I dragged the PC76 out to see if it still ticked. It looks like the channel spacing is off on the modified frequencies, If you have more than the usual 40 it might get worse... 19+10k is spot on, 40+10k is 80 high and 1+10k is 80 low. I've seen AM radios being used at 300 off, so its no big...
  3. MKwrench

    Cobra 29LTD/GTL 10 KC mod????????

    I know this is an older thread, but I wanted to share some of my experiment results. This was with a Uniden PC76XL, it's about the same as the Cobra 29s inside. Cut the rearmost trace on the 10.24, remove C131 and bridge the cut trace with a 22pf trimmer and the lower half of the CH9 switch...
  4. MKwrench

    Cobra 29 High Power mod with 2sc1969 transistor

    I used one (HG2312) in a pinch to repair a side mic. 29 LTD a while back, then monkeyed around with some trial and error stuff. It seems to make easy power the way it is. A clean 23pep without tweaks. These are from my notes some add a little more oomph, or help keep things sharp and clean...
  5. MKwrench

    Grant 999AD AMC/ALC Problems

    I had mentioned above that I added an "NPC" mod at an earlier point. My notes on this radio were that replacing the 560ohm R282 with a 1K with a 4148 and 220ohm in series, parallel to it, works awesome. I don't "volt" the finals, I never find much to gain in it unless it has a MOSFET driver...
  6. MKwrench

    Grant 999AD AMC/ALC Problems

    Okay.... Who did this??? Ohh $#!7! It was me ...... Whoops!Yep that's backwards As soon as it was corrected, everything went smooth as butter. Thanks for not cursing me out for trying stupid mods on this radio (on my post anyhow) ...lol Here's some more pics and video.
  7. MKwrench

    Easy Grant PC409 Clarifier Unlock

    I like my older radios, most were discarded by someone else and snatched up for parts and experimentation. Mine always end up as living breathing functioning works of love. Even after freshening up, some of my radios drift with temperature. Being in the Cleveland area, my mobiles can see...
  8. MKwrench

    Grant 999AD AMC/ALC Problems

    I think I know where the problem might be, but thought it would be cool to share as I undo a few audio cap changes that I thought would "open up" the audio a little more. The issue is with the ALC and AMC adding weird distortion and oscillation that will continue without any added audio while...
  9. MKwrench

    L39, 470nH Substitute

    That's really cool! I always thought there was some "magic formula" that calculated the 500nH value. I'm going to try this in the morning. These .5uH chokes are so common in radios, but a PITA to find. I have to go to that site to play with that calculator too. Thank you!
  10. MKwrench

    L39, 470nH Substitute

    Thank you, very much!
  11. MKwrench

    L39, 470nH Substitute

    Hi everyone, I smoked L39, the .47uH inductor near the finals in one of my PC409 Grants. I'm sure someone else may have been, or will be in this situation. Without any HG 2SC1969, or similar for replacements onhand, I installed the IRF520 and related components. I have a few others that...
  12. MKwrench

    Home January New Year's Giveaway: 3 Retevis Ailunce HA1UV Radios!

    I understand the rules and would like to enter.
  13. MKwrench

    PC66 with ??? Channel expander.

    I ended up swapping out a few suspect caps and put the supply back on 8v with a choke, in case the distortion was from RF bleeding to +. After I poked around with the scope in a few spots, the distortion went away, but came back after the radio sat a few hours. (time for a full recap ???). * I...
  14. MKwrench

    PC66 with ??? Channel expander.

    After removing the "epoxy deal" I was able to chip the back of the board clean because the builder forgot to clean up the flux. After reflowing a few spots, it was working again. I hooked it up with jumpers and was able to tune 26.965-27.405 on "C" and 27.415 to 27.855 on "D" again not touching...
  15. MKwrench

    PC66 with ??? Channel expander.

    Ya, I dont think it's an "Expo" brand kit. Does have 4 Xtals and 4 trim caps, I havn't measured the frequencies yet. I may have damaged the "Epoxy" board by feeding it full voltage, I moved it to 8v, but now have nothing in any band, missing the "front" oscillator now. I'm going to look for...
  16. MKwrench

    Service information for GE 3-5805

    That one is on the driver and was empty, one of the 1st things I did when the covers were popped off was to drop a slug in and got another 4w PEP before the swing mod was added, but made no difference after. I think L10 is just there to keep RF out of the audio/power (simular to L11). It'll all...
  17. MKwrench

    Service information for GE 3-5805

    The original L1 had an "accident" with D7 (who doesnt look happy either), while I was doing some measurments. .......Whoops! .......(still stinks inside) One thing I plan on using a schematic for, is to see if I can widen up the audio band a little by swapping some caps. I was abe to...
  18. MKwrench

    Service information for GE 3-5805

    Thanks S/S Im going to look that over to see if we have a match when I get a chance. I grabbed a few quick snaps before dinner to add. The board #: " PC852AA" . You can see my "Swing-A-Roo" (w/yellow wire), and L1 from a parts radio, in the 2nd pic...
  19. MKwrench

    PC66 with ??? Channel expander.

    I forgot to add pictures. The pictures are the best part! Does anyone recognize these? I can't get back to this radio untill Thursday to try the 8V supply, It looks like I could add a ground besides the one in the "mini coax". What are your thoughts on this?
  20. MKwrench

    PC66 with ??? Channel expander.

    I like these old PC66s and grab them up when they are cheap or "for parts". This one has a channel mod that was installed improperly. It wouldn't transmit or receive when I first tried it out. The ground and input were reversed on the "switch/xtal" board to the add-on "tune board". After...