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Topic: National New Yorker - wiring problem |
William Steward
From:
Grand Cayman, Cayman Islands
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Posted 6 Jun 2004 7:17 am |
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| I recently acquired a 1957 vintage 6 string National New Yorker from a friend. After re-stringing it, to my dissappointment I plugged it in to find it has a loud hum and faint signal. When I touch the pickups both the hum and signal stops. I have removed strings and the opened up the combination taipiece and pickup mixing control pot mounting plate - wiring appears fine and undisturbed. I have cleaned the volume and mixing pots with some tuner cleaner, removed old string bits from the inside but still no joy. I assume the plug-type jack was original and not replaced as with some of the older models with the 'amphenol' type. The jack has been cleaned and the contacts seem OK. Any other tips for trouble-shooting? I am putting this in 'No Pedalers' rather than 'Electronics' since I know some of you guys will know the peculiarities of this model National. |
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HowardR
From:
N.Y.C.-Fire Island-Asheville
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Posted 6 Jun 2004 8:50 am
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Hi William.
You might try the search function as there were a couple of threads not too long ago with regard to the internals of National NYKers. There are hidden pick ups in the neck, and that may be the source of your problem. |
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Steinar Gregertsen
From:
Arendal, Norway, R.I.P.
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Posted 6 Jun 2004 9:17 am
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| Quote: |
| There are hidden pick ups in the neck, |
Howard, are you sure about that? I believe it was some of the older late '30s or early '40s that had the hidden pickups..
Anyway, there's no such things in my '57 New Yorker, and from Williams description it sounds as if there is a serious grounding hickup in the guitar.
I'm sure it's 'fixable' though, but I can't say how without inspecting the pickup,- Professor Aiello?
Steinar
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www.gregertsen.com
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HowardR
From:
N.Y.C.-Fire Island-Asheville
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Posted 6 Jun 2004 9:49 am
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The only thing I'm sure of is that William will find the solution on this forum. That's why I suggested reviewing previous threads.
Hidden neck pups in the older models sure came as a surprise to me.  |
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Rick Aiello
From:
Berryville, VA USA
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Posted 6 Jun 2004 10:05 am
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| Quote: |
| When I touch the pickups both the hum and signal stops. |
Its perfectly normal for hum to dissapear when the strings or metal components are touched ...
Noise Bucket
... but not the signal.
| Quote: |
| I plugged it in to find it has a loud hum and faint signal. |
Smells like a coil problem ... I've had shorted coils that still put out some signal ...
A rewind may be in order ...
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www.horseshoemagnets.com [This message was edited by Rick Aiello on 06 June 2004 at 11:13 AM.] |
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Bill Bosler
From:
Schwenksville, Pennsylvania, USA
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Posted 6 Jun 2004 1:13 pm
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| Sounds to me like the volume pot or jack is wired backa$$wards. I had the same problem with an old Supro I picked about 6 months ago. |
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Doug Beaumier
From:
Northampton, MA
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Posted 6 Jun 2004 1:45 pm
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Try removing the top plate of the pickup and reverse the magnets. The magnets are on each end of the pickup housing.
My local guitar repairman was rewiring an old New Yorker for me a few years ago. He told me that he couldn't get much response from the pickup until he switched the magnets, and then and it worked fine. He said someone must have removed them at one time and put them in backwards or in the wrong end.
The "hidden pickup" was in the pre-war New
Yorkers. It was under the fretboard. That
feature was discontinued by the early '40s.
My Site - Instruction | Doug's Free Tab | Steels and Accessories
[This message was edited by Doug Beaumier on 06 June 2004 at 02:48 PM.] |
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Steinar Gregertsen
From:
Arendal, Norway, R.I.P.
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Posted 6 Jun 2004 2:43 pm
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Doug,- you're referring to the string-through pickup that some NY'ers has, don't you? I doubt that's the same pickups that's on Williams, unless National really got the pickups mixed up.
Here's a photo of the pickups on my '57 New Yorker,- are these the same that's on your '57 William?
Steinar
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www.gregertsen.com
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Chuck Fisher
From:
Santa Cruz, California, USA * R.I.P.
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Posted 6 Jun 2004 2:45 pm
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get an ohmmeter cheepies are 15 bucks at radio shack
1) check coil it should read 4 - 15 k ohms
2) look for wires physically off
3) strings should be near zero ohms when checked to the ground-side of outpiut jack.
across the outside 2 of tone and vol controls 3 terminals, the ohmmeter should read 100 - 500k ohms or it should be equal to the pickup's coil resistance.
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Doug Beaumier
From:
Northampton, MA
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Posted 6 Jun 2004 4:01 pm
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| Steinar, Yes... I was referring to the string-through pickup. I didn't realize that the '57s had a string-over-pickup. Thanks, DB |
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William Steward
From:
Grand Cayman, Cayman Islands
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Posted 6 Jun 2004 7:44 pm
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| Gee thanks guys....it is unlikely that the magents or wiring of volume control may have been changed but will save those as options after checking the resistance of the magnets (thanks for the info on that Chuck). There is clearly may be a grounding problem somewhere....and Steiner yes my pickups are identical to the ones in your photo. hmmmmmmm I think I will start with the resistance test - I have a cheapy Radio Shack multimeter (and even that I have had to repair myself!). Thanks everyone....will let you know how I make out. |
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William Steward
From:
Grand Cayman, Cayman Islands
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Posted 6 Jun 2004 8:15 pm
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| Resistance at the pickups is 12K and 2.5K...no resistance on the poles of the tone control - maybe this could be a problem? The volume control is harder to get at but seems to control the volume of the hum so can I assume it is working? |
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William Steward
From:
Grand Cayman, Cayman Islands
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Posted 6 Jun 2004 8:31 pm
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| could not find anything in previous posts in Electronics or No Peddlers that sheds any more light on this specific problem.....perhaps I missed something? I am relieved that the pickups seem to check out since that is the component that would be hardest to repair here in the tropics! That pot for blending the two pickups - can anyone tell me what spec would I replace it with? I don't see much written on it. [This message was edited by William Steward on 07 June 2004 at 06:17 AM.] |
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Chuck Fisher
From:
Santa Cruz, California, USA * R.I.P.
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Posted 7 Jun 2004 2:33 pm
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a schematic would be helpful, anybody???
the radical difference in the pickups is suspicious, (if you are saying one pickup is 2.5k and the other is 14k) the 2.5 k one might be a shorted coil. Also the controls should be all-up clockwise if this is somewhat normal guitar wiring. the tone pot might be as high as 1 megohm, but I doubt it, usually these are 100-500 k.
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Steinar Gregertsen
From:
Arendal, Norway, R.I.P.
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Posted 7 Jun 2004 2:51 pm
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There is no tone pot on this model, it's a blend control for the two pickups. At least that's how it works on mine.
Let me know if you figure out how to access the volume pot William, I would really like to know (not that I need to, the volume control on mine works great, but still....).
Steinar
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www.gregertsen.com
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Chuck Fisher
From:
Santa Cruz, California, USA * R.I.P.
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Posted 7 Jun 2004 3:14 pm
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| these are interesting guitars, is the volume pot the one dead-center behind the bridge? |
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Steinar Gregertsen
From:
Arendal, Norway, R.I.P.
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Posted 7 Jun 2004 3:24 pm
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The volume control is on the treble side of the string, in front of the pickups, perfectly placed for easy access. The blend/tone control is the 'chicken' knob behind the bridge, with a scale going from 0-100.
Steinar
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www.gregertsen.com
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Chuck Fisher
From:
Santa Cruz, California, USA * R.I.P.
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Posted 7 Jun 2004 3:36 pm
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well if Steinar's should get opened some measurements and wiring snapshots would help this a bit, comparing the coil and vol and blend pot resistance would be useful.
is this the same vintage Freddie Roulette plays?
if all else fails, individually connect each coil to an amps input via direct cord w/ alligator clips.
at this point either pot or 1 coil could be bad, i think the 14k coil is good. if i had a schema i'd have a more streamlined troubleshooting proceedure for you. |
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HowardR
From:
N.Y.C.-Fire Island-Asheville
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Posted 7 Jun 2004 3:50 pm
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| I thought Freddie Roulette played a National Dynamic. |
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William Steward
From:
Grand Cayman, Cayman Islands
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Posted 7 Jun 2004 8:53 pm
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| The blending pot had a (capacitor?)on it labelled RMC JL4700 20% which has now broken due to me pulling the wiring in and out. Maybe it wasn't essential anyway but will see if Radio Shack has a replacement. I guess I will try isolating the pickups as you suggest Chuck. I assumed that the difference in resistance would be for tonal characteristics. |
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Rick Aiello
From:
Berryville, VA USA
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Posted 8 Jun 2004 4:19 am
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I remaged a pair just like the ones in the photo ...
The DC resistance for each pickup was the same ...
I seem to remember them being in the 12K ohm neighborhood
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www.horseshoemagnets.com [This message was edited by Rick Aiello on 08 June 2004 at 08:52 AM.] |
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William Steward
From:
Grand Cayman, Cayman Islands
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Posted 8 Jun 2004 5:27 am
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| Rick....I am going to pick up some alligator clips today and try bypassing the pickup or blending pot to see which is causing the problem. Thanks guys....I was hoping to take this old thing with me to Ohio this week for the workshop with Cindy Cashdollar. |
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William Steward
From:
Grand Cayman, Cayman Islands
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Posted 8 Jun 2004 8:24 pm
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| The alligator clips were the best diagnostic tool I could buy for under five bucks! I tried the pickups individually - since they checked out it seemed to point to the wiring in between the jack and the pickups (duh). I have temporarily patched a wire between the hot lead of the pickup jack and one of the poles of the blending pot, effectively bypassing it. The hum stopped and at least I have a guitar to play. I will get Forumite Walter Jones to help me look at it when I am up in Ohio this week. Any reason why a stereo balance control would not work as a replacement for the blending pot? Thanks everyone for your advice!!! |
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Chuck Fisher
From:
Santa Cruz, California, USA * R.I.P.
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Posted 9 Jun 2004 12:37 pm
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Let me preface this with I know nothing of National wiring in particular but I know guitar wiring.
the blend pot is looking like the culprit,
* is this a stacked double with 6 terminals?
* or a single with 3 terminals.
if the latter is the case, is one lead from each pickup coil going to each end and the output jack + (tip) going to the center (wiper) terminal ?
where did the capacitor connect?
did both pickups give you sound when isolated?
we'll get this...
PS I love these guitars' look, its just SO DECO!!! It looks like toast should come out of it or something.[This message was edited by Chuck Fisher on 09 June 2004 at 07:58 PM.] |
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