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Author Topic: Vibroplex Brass Racer EK-1 problems  (Read 413 times)

W3WN

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Re: Vibroplex Brass Racer EK-1 problems
« Reply #15 on: April 02, 2022, 07:26:20 PM »

Was the EK-1 available with a choice of either the 8044 or 8044B IC, the B suffix meaning Curtis mode B?  To date, I've only seen the 8044 mode A version of the EK-1.

Paul, W9AC
Not that I knew of, back when I worked at a ham dealership.  Just the “A”.
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W9AC

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Re: Vibroplex Brass Racer EK-1 problems
« Reply #16 on: April 03, 2022, 06:58:24 AM »

Brett,

How have you determined that Q1 and Q2 have failed?  By removing each transistor from the board and taking VOM measurements?  For measurement purposes, a BJT transistor looks like two back-to-back diodes. 

Because you're limited to a VOM for testing, have a look at W2AEW's informative video.  He uses a VOM for transistor testing.  Video link below: 

https://www.youtube.com/watch?v=qM7_h8my8eA

If you still cannot get it working, send it to me and I'll repair it for free.  I have all components for the repair including a Curtis 8044 A mode chip I'll never use.

Paul, W9AC
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W9AC

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Re: Vibroplex Brass Racer EK-1 problems
« Reply #17 on: April 06, 2022, 03:56:28 PM »

Quick follow-up...

I recently discovered that the original MFJ 422-X keyer (non-B or C suffix) were all sold with an original 16-pin Curtis 8044B chip.  Later Curtis chips were either 18 or 20-pin devices as discussed above.  This means the 16-pin Curtis chip can be extracted from the MFJ keyer and used in the Vibroplex EK-1 paddle for Mode B operation or in my case, used in a Curtis "Lil Bugger" keyer. 

The MFJ 422 came with a Bencher BY-1 paddle while the "422-X" version could be purchased as a stand-alone keyer but can still attach to a Bencher paddle. 

Used 422-X keyers can be found on the used market; a lot of them were sold in the mid 1980s. I recently found a few in butchered condition but the Curtis chips are fine.   

Paul, W9AC
« Last Edit: April 06, 2022, 03:58:31 PM by W9AC »
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W9IQ

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Re: Vibroplex Brass Racer EK-1 problems
« Reply #18 on: April 06, 2022, 06:12:48 PM »

Great detective work, Paul!

- Glenn W9IQ
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.
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