Radio wiring
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=33315
Printed Date: 10 Sep 2025 at 11:57am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Radio wiring
Posted By: Russ-neia
Subject: Radio wiring
Date Posted: 04 Jul 2011 at 8:24pm
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Putting new guts in my A-C fendermount radio. The new receiver has four wires for two speakers. I'll only be installing one speaker. Do I just isolate and tape off one set of speaker wires or should I pair the positives and negatives up and connect both sets to the one speaker? Also, the receiver says 12v negative ground. Can I connect it to my D-17 positive ground system without ruining anything? I assume just reverse the wires and should be OK? ------------- The innovators offer what others will imitate. |
Replies:
Posted By: Tedin NE-OH
Date Posted: 04 Jul 2011 at 8:27pm
| you can not connect it to a 12 v positive ground |
Posted By: Russ-neia
Date Posted: 04 Jul 2011 at 8:34pm
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So, you're saying I'm SOL on using this receiver and look for a different one to use with the D-17? ------------- The innovators offer what others will imitate. |
Posted By: Jeff Z. NY
Date Posted: 04 Jul 2011 at 8:53pm
| You can get a power {polarity} inverter for the radio. |
Posted By: Stan IL&TN
Date Posted: 04 Jul 2011 at 9:03pm
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The radio won't care that the tractor is positive ground as long as the polarity is correct going to the radio. The problem is that you would have to isolate the chassis of the radio from the tractor chassis because the radio will have a negative chassis and the tractor will have a positive chassis. So you know what happens when the two meet for the first time. It won't be pretty. ------------- 1957 WD45 dad's first AC 1968 one-seventy 1956 F40 Ferguson |
Posted By: Jeff Z. NY
Date Posted: 05 Jul 2011 at 8:33am
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If you isolate the radio chassis and run wires to hook it up normal dont't forget the antenna base will also have to be isolated from the chassis.
It will get ground from the radio through the antenna wire. If it doesn't play well you can put a capacitor between the chassis of the tractor to the ground of the antenna without a short. Send a PM if you need info. |
Posted By: Coke-in-MN
Date Posted: 05 Jul 2011 at 9:35am
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Had the same problem with White truck I have that was + ground. I used a piece of 1/2" PVC sheet and attached it to the cab, then attached the raido to the PVC.I made sure the mounting bolts were not touching in any way to each other .
As the antenna is already insulated it attached directly to body or in your case attach it to the radio box.
If the radio is a sterio and you only use one speaker, you may get only part of output. Might find a small speaker to mount the other set of leads to and mount into box. ------------- Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel. |
Posted By: Gerald J.
Date Posted: 05 Jul 2011 at 11:44am
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Modern solid state radios don't survive connecting the two speaker lead sets in parallel. Smokes the IC. They also don't survive grounding a speaker wire nor reversed polarity, not even for an instant. With one speaker it will work on AM because AM is mostly mono and there are few AM stereo receivers about, and often you can switch FM to MONO then one speaker is fine. Or set the fader control to the one speaker which will put both sides of the stereo signal on that one speaker. And you will notice greater range on FM MONO than FM stereo. I'd expect most antenna mounts to be grounded at the mount to make the antenna work better so that coax is a problem when trying to float the radio for use with positive ground. I think Shoup carries a tractor radio with switchable polarity. Such were common in the 1960s for cars and trucks. Unless you have already put in a positive ground electronic ignition, its not hard to switch a tractor's polarity, change the battery connectors, swap the primary connections on the coil, swap the ammeter connections, and flash the generator before starting. Label the battery connections well so its not accidentally reversed to original. Gerald J. |
Posted By: Jeff Z. NY
Date Posted: 05 Jul 2011 at 4:27pm
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Like I said the antenna will ground through the coax from the radio chassic that is floating and wired - ground when the antenna mount is isolated from the chassis of the tractor that is + ground.
If reception is bad a capacitor from the + ground chassis to the floating - ground antenna mount will help. Send PM for capacitor hook up and values. |
Posted By: jaybmiller
Date Posted: 05 Jul 2011 at 4:42pm
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How about converting the D-17 to -ve ground ?
Be a WHOLE lot safer than floating the radio 'cause when the radio chassis gets 'grounded' to the tractor with say a screwdriver, a set of keys, etc. sparks will surely fly !
------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: Jeff Z. NY
Date Posted: 05 Jul 2011 at 4:55pm
| Protect it with a low amp fuse also. |
Posted By: Jeff Z. NY
Date Posted: 05 Jul 2011 at 5:06pm
| If it was me and I really wanted to keep the tractor wired the way it is I would just buy a power {polarity} inverter. |
Posted By: Gary in da UP
Date Posted: 05 Jul 2011 at 5:08pm
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No worry, the Brits have what you need if things go badly. 
|
Posted By: redline
Date Posted: 05 Jul 2011 at 5:30pm
------------- If it weren't for the last minute, I wouldn't get anything done! |
Gary in da UP wrote:Posted By: Coke-in-MN
Date Posted: 05 Jul 2011 at 5:36pm
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When your dealing with the Prince of Darkness LUCAS, you have to remember Lucas lighting has three stages flicker, dim, and off (dark)
Then one curses the British electrical system on their motorcycles but forgets Lucas was the low bidder on systems. Then at the same time one has to remember the Lucas electric Magnetos were used on most planes that defeated the Luftwaffe in WW2 ------------- Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel. |
Posted By: redline
Date Posted: 05 Jul 2011 at 8:40pm
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Yep, I am learning that there is usually a reason the low bidder is the lowest bidder. They have learned how to skimp on quality and to cut corners, generally speaking. Every once in a great while it does happen that the bidder doesn't feel like gouging as hard as the others, though. ------------- If it weren't for the last minute, I wouldn't get anything done! |