Collins 30L-1 , parts ?

Discussion in '"Boat Anchor" & Classic Equipment' started by KD0CAC, Sep 22, 2010.

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  1. KD0CAC

    KD0CAC Ham Member QRZ Page

    In the process of repairing this new to me 30L-1 , I'm having issues finding a few parts .
    A couple of resistor values are harder to find than I thought ,
    BRN-BLK-BLK-SIL , 10 ohm 2 watt carbon composition , need 2 of these min.
    ORG-BLK-BLK-GLD 3 ohm 2 watt " " , need 1 of these ,
    Tuning coil L-16 , all of the coating was burn off , I may rewind , but in case the slug is damaged a replacement .
    Found some NOS tubes .
    Thanks John
  2. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

  3. KD0CAC

    KD0CAC Ham Member QRZ Page

    I've been there but just did a lot reading , downloaded the service bulletins , which make for another list of parts .
    It does seem to be that the forms is somewhat inactive ?
  4. KJ4OLL

    KJ4OLL Ham Member QRZ Page

    try the other Collins group,
    Collins Radio Association
    I had many responses and helpful info. from the wonderful CRA folks.
    Bought mods for my 30L-1 from Young Kim, super!! Found him in the CRA newsletter.
  5. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    I subscribe to both of the Collins reflectors. Frankly, the CCA reflector is considerably more active than the reflector which is basically the CRA reflector.

    You can sign up for the Collins reflector by going to and then finding the Collins reflector in the list of reflectors. "Click" on the link and then follow instructions.

    Glen, K9STH
  6. W8JI

    W8JI Ham Member QRZ Page

    You can't hardly buy a carbon comp any longer. They are all custom order. That is why we quit buying them commercially for products.

    Look at this picture:


    Carbon films and carbon comps often look identical, and are often sold incorrectly (especially between hams).

    The perfect better substitute that has much better life is a metal composition. An Ohmite OX or OY series would be ideal. If you get really stuck, I have some 10 ohm 2 watt. I'm not so sure about a 3 ohm. I think only 2.7 or 3.3 are common.
  7. KD0CAC

    KD0CAC Ham Member QRZ Page

    Not a electrical engineer , yet , so I do not know what I can substitute with ?
    I have been told not to use metal film or wire wound , because of RF issues ?
    The 2 BRN-BLK-BLK-SIV are in parallel in the power side of the chassis , one end to board , the other end to a pass-through into the RF side .

    The other I have not found in the wiring diagram yet , it connects to the 239 RF connector mount screws , then a couple wires take off onto the chassis .
    This one is ORG-BLK-BLK-GLD

    I was given a bag of resistor , about 2 ft. around mostly carbon comp. , took about 3 days to sort , still have to sort the 1/8 & 1/4 watt , ran out of drawers & cabinet space .
  8. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    One thing about the old carbon composition resistors is that they can change value, often considerably, over the years. It is best to use an accurate DMM to check the actual resistance. Also, remember that the tolerance of the resistors was a lot greater than tolerances today. No 4th stripe means 20 percent tolerance, a silver stripe means 10 percent tolerance, a gold band indicates 5 percent tolerance. Some of the old "dog bone" type resistors had a tolerance of 30 percent!

    Most of these resistors tend to go "high" in value. Although not usually that much, I have run into resistors that have gone to over 10 times the original value yet show no outward signs of any abuse, etc.

    Glen, K9STH
  9. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Another thing, orange black black gold is NOT a 3 ohm resistor! It is a 30 ohm 5 percent resistor. If you put in a 3 ohm resistor you may destroy the 811A tubes because the bias voltage will not be correct. However, that resistor, along with several others, really needs to be changed. This per Collins Service Bulletin 3 for the 30L-1. You can download this Service Bulletin at

    Glen, K9STH
  10. KD0CAC

    KD0CAC Ham Member QRZ Page

    Ya I was looking at that a while back , went to a local tube radio repair place and during a quick conversation he jotted down the values , latter looking up the color codes , I thought for a second that should have been 30 instead of 3 , but did not write it down .
    Now I have to use that value and see if my search comes up with better results ?
    I have down loaded all the documents , including the service bulletins .
    I need to make a list of what is in the amp , then look for updates to see if any have been done , at this time I was just looking for what was in the amp , make a list of how it was built when I got it , then compare with SBs .
    By the time I think I'm ready , I should be a little more familiar with it ,
    and amps in general .
    This is how I have acquired most of my stuff [ everything including cars etc ] get an idea of what I want , find a broken one , or two and fix it .
    This is one thing that excites me about ham radio .
    Its too bad that the evolution of these things and there parts are getting to go beyond what anybody that does not have a lab can play with .
    I'm referring to the miniaturization of parts , I do not mind surface-mount , the first couple of generations , but when they get so small that you need optics [ with good young eyes ] and equipment that handles such small parts .
    On top of from what I hear , parts are getting harder to get access to .
    Thanks again
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