1. 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.
    Dismiss Notice
Dismiss Notice
This forum does not allow a single user to have more than one username. If anyone wants to change their username contact an admin and it will be done. Multiple accounts belonging to the same member will be deleted without warning.

Palomar Digicom 100 by CPI

Discussion in 'CB Radio Modifications' started by 357, May 16, 2021.

  1. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    I picked one of these up and was wondering if anyone has any info on it and the chip.
    It would be nice to open it up to 40 channels or even 99



    digicom100_9.jpg digicom100_6.jpg digicom100_3.jpg
    link to images
     

  2. nomadradio

    nomadradio Analog Retentive

    Joined:
    Apr 3, 2005
    Messages:
    4,715
    Likes Received:
    6,261
    The EPROM in the pic translates the 8-bit BCD binary code from the front-panel knobs to the correct binary code for the PLL. The 5203 was made by a competitor of Intel, and used a different pin layout from Intel's ROMs. Intel's setup is what the rest of the industry copied and/or licensed. Pretty sure the 5203 was a Signetics design. If it fails, someone will have to hack a substitute of some sort. Can't remember the last time I saw a programming device that could write a blank one of those.

    The PLL is composed of the 74-series logic chips wrapped around the ROM. Single-chip PLLs were just being introduced when this radio was designed.

    I remember this radio as a good sideband performer, but a bit lame on AM transmit. Seems to me there was a hack to expand the channel coverage but it's been too many decades since seeing the last one of these.

    The transparent cover of that kind of EPROM was usually covered with a label of some sort. I wouldn't expose it to too many weeks of indoor fluorescent light. They were meant to be erased by an intense UV light so they could be reloaded. They say a few days outdoors in the sun would do it. Indoor fluorescent light a bit longer.

    73
     
    NZ8N and 357 like this.
  3. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    Thanks Nomad. I was pretty sure you would know something about these.
    Google shows very little.
    Hopefully it has 99 already it will be here Monday.
    looks similar to the CPI CP300

    God Bless
     
  4. tramd

    tramd Active Member

    Joined:
    Jul 17, 2009
    Messages:
    57
    Likes Received:
    80
    Here's a schematic for it. I believe there is a CPI group on FaceBook that used to be on the old Yahoo group. Might find some info there.
     

    Attached Files:

    357 likes this.
  5. Dr_DX

    Dr_DX Well-Known Member

    Joined:
    Jan 29, 2006
    Messages:
    181
    Likes Received:
    193
    tecnicoloco and 357 like this.
  6. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    For your viewing pleasure...she's a runner

    IMG_0786.JPG IMG_0787.JPG IMG_0788.JPG IMG_0789.JPG IMG_0790.JPG IMG_0791.JPG IMG_0792.JPG IMG_0793.JPG IMG_0794.JPG IMG_0795.JPG
     
    Shadetree Mechanic likes this.
  7. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    IMG_0796.JPG IMG_0797.JPG IMG_0798.JPG IMG_0799.JPG IMG_0800.JPG IMG_0801.JPG IMG_0802.JPG IMG_0803.JPG IMG_0804.JPG IMG_0805.JPG
     
  8. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    IMG_0806.JPG IMG_0807.JPG IMG_0808.JPG IMG_0809.JPG IMG_0810.JPG IMG_0811.JPG IMG_0812.JPG IMG_0813.JPG IMG_0814.JPG IMG_0815.JPG
     
  9. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    IMG_0816.JPG IMG_0817.JPG IMG_0818.JPG IMG_0819.JPG IMG_0820.JPG IMG_0821.JPG IMG_0822.JPG IMG_0823.JPG IMG_0824.JPG IMG_0825.JPG
     
  10. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    IMG_0826.JPG IMG_0827.JPG
     
  11. unit_399

    unit_399 EL CAPO

    Joined:
    Jun 17, 2008
    Messages:
    1,592
    Likes Received:
    1,330
    Really tight old school rig. Cleaned up nice.

    Here's some background info from Radio Museum.org
    $495.00 in '76 was a bundle .
    (BTW - SCHEMATIC and alignment info in Sams CB-103)
    - 399


    CPI100.png
     
    #11 unit_399, May 18, 2021
    Last edited: May 18, 2021
    NZ8N, Shadetree Mechanic and 357 like this.
  12. Big Kahuna

    Big Kahuna Sr. Member

    Joined:
    Jul 31, 2008
    Messages:
    1,066
    Likes Received:
    1,860
    That is really cool! Can you explain the channel selector knobs? That seems to be very unique.
     
    357 likes this.
  13. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    She's a work in progress.
    Looks a bit better. That switch though...I gotta find a LED or something the put there.
    It only does A channels so it useless nowadays.

    IMG_0828.JPG IMG_0829.JPG IMG_0830.JPG IMG_0831.JPG IMG_0832.JPG IMG_0833.JPG IMG_0834.JPG IMG_0835.JPG
     
    NZ8N and tecnicoloco like this.
  14. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    the left knob on 1 and the right knob on 9 would be channel 19.

    The 1 knob skips 4 and 5 and added another 0 and a 1....not sure why yet.

    I see I got to swap them back but 38 is 72 and it goes 5KC steps after a certain point.
    I'm just glad it covers 40 channels because if it didnt I'd be screwed.
    Someone must have made custom chips at some point
     
    NZ8N and Shadetree Mechanic like this.
  15. 357

    357 Walkin' the dog

    Joined:
    Sep 12, 2009
    Messages:
    1,210
    Likes Received:
    628
    IMG_0802.JPG

    Here is the chip for the PLL and I'm happy to report it covers to at least channel 40
    Radio is working but I need to find the ALC bad
     
    NZ8N likes this.

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!