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Author Topic: Ajusting a used Bencher & What's that M4x8max bb on top?  (Read 6021 times)
W0XI
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Posts: 67




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« on: June 19, 2010, 02:06:30 PM »

Been off HF for years. Getting the itch again. Found a used Bencher (silver) with black box on top. Read several threads on "adjustment of" and it seems to be working aok. I don't like the tone of the CW coming out of the black box. My use combo with homebrew QRP rig so may want to keep the keyer (BB?). Any advise on adjustment and what the BB is?

73s, Phil, W0XI (ole dude).  Angry
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WB2WIK
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Posts: 20636




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« Reply #1 on: June 19, 2010, 02:09:46 PM »

I have three Benchers and none of them have any adjustments "on top" at all.

Nor is there any "black box" on them.

Can you post a photograph of what you have somewhere?
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AA1BN
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Posts: 56




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« Reply #2 on: June 19, 2010, 03:12:24 PM »

That keyer isn't cheap:
http://www.radioworld.co.uk/~radio/catalog/mfj422dx-compact-keyer-module-without-paddle-p-3172.html?currency=USD

The manual for that model is here:
http://www.difona.de/pdf_en/mfj422d_manual.pdf

Good luck, es 73

John
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WB2WIK
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« Reply #3 on: June 19, 2010, 05:08:47 PM »


That's a real assumption that might be what he has.  However, I must say I do have an MFJ-422 here, which is a Bencher paddle with a keyer mounted atop it, and it doesn't have any "top" adjustments, either!  In fact, it's a sealed box that you would only remove from the paddle (using a single Philips screw on the bottom) to replace its battery. 

The Bencher paddle has no "top" adjustment; it has two "side" adjustments, for contact spacing, and two "front" adjustments for spring tension, and that's all it has.
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W0XI
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Posts: 67




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« Reply #4 on: June 19, 2010, 07:40:35 PM »

Reference WB2WIK,

Hi. Thank you for your response. I posted two pictures on my website. Try this:
www.midnightscience.com/w0xi

Let me know if that page doesn't work. It's a page off the main site.

Clearly the paddle is a Bencher but not sure of date or model. Seems to work ok. I've adjusted the gaps to one paper thickness and set the tension screws at 1/2 out. There was a black-box keyer that came mounted on top of it; clearly home brew after I took it off the paddle. Don't care for the raspy sound. Any info would be helpful.

Thinking I'll build my own keyer (or put one in the rig) since I have no schematic for the homebrew  and it is pretty kludgy).

Thanks for your help. Phil Anderson, W0XI.
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AA1BN
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Posts: 56




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« Reply #5 on: June 19, 2010, 08:48:54 PM »

The Link doesn't work, Phil.

I suppose I misunderstood the question! I thought you meant
the adjustment was on that "black box".

My iambic Bencher has no "top" adjustment, although single paddle keys
may have a top adjustment.

My non-iambic El-Key has such an adjustment, and it's to set the pressure
on the paddle shank support; the pin that the shank rides on.

A picture would be best.

Very 73,

John
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W0XI
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Posts: 67




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« Reply #6 on: June 20, 2010, 07:02:04 AM »

AA1BN, John,

Try this address, adding a ./html

www.midnightscience.com/w0xi.html

73s & thanks, Phil, W0XI
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WB2WIK
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Posts: 20636




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« Reply #7 on: June 20, 2010, 11:30:18 AM »

That link worked and I looked at the picture -- it's the same as my three Bencher paddles.

What top adjustment are you talking about?  I don't see any on my paddles, or in your picture.

There are only four adjustments, total: The two on the pillars to adjust contact spacing, and the two screws that go in at angles into the two "C" shaped armature units; those adjust spring tension, and it's not much of an adjustment.

That's all there is!
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KA5N
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Posts: 4380




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« Reply #8 on: June 20, 2010, 01:39:00 PM »

Since the keyer is homebrew and you don't have any info on it, it is pret near impossible to give you any advice on how to fix it.  One way to get rid of the raspy sound is to disconnect the speaker and listen to the side tone on your transceiver.  You could try a pot with a different taper to avoid the squeeze at the high end.  i.e. if the taper is linear try an audio taper.
Allen
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VA7CPC
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Posts: 2406




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« Reply #9 on: June 20, 2010, 04:56:51 PM »

If all else fails, try a PicoKeyer.   Inexpensive, with good reviews.

http://www.hamgadgets.com/store/product_info.php?products_id=89

It may be quicker to order and build the PicoKeyer kit, than to fix what you have.

Your Bencher setup sounds good.  The Bencher BY series has been pretty much unchanged since the late 1970's or early 1980's.

             Charles

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AA1BN
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Posts: 56




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« Reply #10 on: June 20, 2010, 08:07:28 PM »

Phil -

After re-reading your initial post, you were asking about adjusting that
keyer, not the key.... ehh? Right? I dunno why we thought you were
asking about a screw on top of the key (bencher)...

That link to that PDF file is one keyer that looks like the one you
have, and there are internal adjustments, just like any other keyer.

You usually can set the ratio of dits and dahs, and spacing,
and go from "a" to "b" iambic..

I have two small Curtis K5 keyers, and as small as they are,
they are fully internally adjustable.

That raspy sound? did you try using headphones in the headphone
jack to isolate the rasp? If it's in not in the headphones, replace the
speaker. It'd be a shame to toss a perfectly good keyer....

Oh well, good luck...

73

John
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W0XI
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Posts: 67




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« Reply #11 on: June 20, 2010, 08:27:14 PM »

Thanks Guys, all good suggestions.

I really like the action of the paddles; as you all seem to say, a keeper.
I just don't like to have a piece of equipment that has no manual or schematic. I'll pull out the IC that's in there; might be a clue. In any event, making/designing a keyer is no large task. I'll keep the current one as a backup. May decide to program a PIC or two; got burners and drawers of pics. Hi. Again thanks guys. Phil, W0XI.
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KE3WD
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Posts: 5689




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« Reply #12 on: June 21, 2010, 10:35:27 AM »

I seem to recall MFJ marketing a keyer box connected to that Bencher at one time. 

Maybe...

At any rate, identifying the keyer chip is the first step.  If it is a common single chip keyer, there's a very good chance that the circuit used is "cookbook" and you can find the basic schematic for it. 

Aside from a bad speaker, other possible reasons for a raspy sound could be as simple as the voltage to the output amp stage being too low, or a possible shorted driver device in the output amp stage somewhere. 

I fyou have a scope, take a look at the output right at the spkr terminals, see if it is a clipped wave, that would be a good clue as to what's going on. 

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AA4N
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Posts: 111




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« Reply #13 on: June 22, 2010, 10:40:52 AM »

I've seen electronic boxes with warnings like "M4x8 MAX"  on them.   This usually refers to the screws in the side of the box.  It means, don't use screws longer than M4x8 or they will touch the electronics inside and short things out, or possibly break things.

So, I'm going with the M4x8 is a metric screw size...

mike AA4N
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W0XI
Member

Posts: 67




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« Reply #14 on: June 23, 2010, 12:44:53 PM »

M4x8, ha, that would be a hoot if that is it. I'm curious now; so will pull a screw out and mesure it - unless you're pulling my leg, ha. Cyptic code makes sense tho.....or maybe it's the DaVinci code for.......Smiley Just replaced the battery and tone changed; better, more crisp, so guessing the output is a square wave hence with steep edges and harmonics. Next these scope and see what the CHIP label has to say. Wheeeeeeee

73s, Phil

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