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XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sat Oct 18, 2014 2:32 pm
by g8tzl2004
Do I need to do the simple ground mod to my XPR6550 programming cable in order to safely program an XPR7550?

I have read that you can damage your XPR7550 or PC if you use an XPR6550 cable WITHOUT the mod.

Is this actually the case? Has anybody damaged their XPR7550?

I have spoken to 3 people who just used an XPR6550 cable to program an XPR7550 with NO problem.

So should I only do the mod if my XPR6550 cable does NOT work with an XPR7550, maybe due to PC voltage issues OR can I really do damage to my XPR7550 by using an unmodified cable??

Thanks

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sat Oct 18, 2014 5:23 pm
by N4KVE
I use a bone stock 6550 A cable on both my 7550's. No problems at all. One radio was one of the first 7550's made, & the other was built just a few months ago. Never had a problem with either. GARY

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sun Oct 19, 2014 5:14 am
by g8tzl2004
Thanks Gary.

I'm wondering if anybody has ever damaged their XPR7550 by using the A cable or whether its just a myth?

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sun Oct 19, 2014 8:41 am
by escomm
It's not a myth. The A revision cable doesn't ground in the same places as the B revision cable. The A revision cable will not actually ground your XPR7550. You might damage the radio, your PC, or both. If there wasn't an issue then Motorola would not have made the modifications and uprevisioned the cable to the B version.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Wed Oct 22, 2014 8:08 am
by g8tzl2004
I'm aware that for some users the A revision cable simply did not work so they did the mod.

But is there anybody who has actually damaged their radio when they unsucessfully used the A cable? Please speak up!!

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Wed Oct 22, 2014 2:38 pm
by jland138
I used the A revision cable on an XPR 5550 while pulling flat audio out of the rear accessory connector and it wasn't pretty.

My wife thinks I'm an idiot, but my dog thinks I'm a genius, so take it for what it's worth.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Thu Oct 23, 2014 12:21 pm
by g8tzl2004
The XPR5500 is a mobile radio and uses a different prog cable. So do you also need to mod the XPR4500 mobile programming cable if you want to use it to program an XPR5500?

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Thu Oct 23, 2014 12:38 pm
by N4KVE
g8tzl2004 wrote: So do you also need to mod the XPR4500 mobile programming cable if you want to use it to program an XPR5500?
I use the same cable [rear acc plug] to program my 4550 & 5550. GARY

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Thu Oct 23, 2014 1:29 pm
by escomm
g8tzl2004 wrote:The XPR5500 is a mobile radio and uses a different prog cable. So do you also need to mod the XPR4500 mobile programming cable if you want to use it to program an XPR5500?
If using the A revision cable, yes, it needs to be modified.

http://en.wikipedia.org/wiki/Ground_loo ... tricity%29

This is relevant to your interests.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Mon Oct 27, 2014 9:47 pm
by KMB
How to modify the cable?
How to identify the A or B ver.?

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Wed Oct 29, 2014 7:21 am
by tdats
KMB, The issue is the A revision cable took it's radio ground from the round antenna connector on the side of the 6500 series radios. On the 7000 series radios, there is no antenna connector in that position, so no cable ground connection.

To modify the cable, open up the radio connector end of the cable and move the wire connected to the pin on the row of 3 horizontal pins down to pin 6 in the rows of vertical pins. I have been looking for the diagram or picture of it on here and am not finding it. I assume the part number label stuck to the cable would say what revision, but I am not sure. The instructions are out there, I am just not having luck finding them today. The modified cable works fine on the 6000 and 7000 radios.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Wed Oct 29, 2014 7:57 am
by N4KVE
The ID tag on my "A" cable is long gone, but there's an easy way to tell which you have. On my "A" cable there is a small device about 6" from the radio side connector that's about 2" long. It has 4 well defined corners. On the "B" cables I have seen, that device is oblong shaped, & has no corners. This should help ID what cable you have if the tag is gone like on my cable. Hope this helps. GARY

This is photo of the "A" cable.

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/ ... yY9VRLb-z/$(KGrHqV,!okFDyjn6GyEBRLb-y(uG!~~60_57.JPG

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Thu Nov 06, 2014 5:46 pm
by com501
Yep. A cable, squarish corners blob, B cable, roundish blob.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sat Nov 08, 2014 8:03 am
by g8tzl2004
UPDATE: I finally got round to programming my XPR7350 and the "A" cable did NOT work!!! I got the following message:

"Error # 1687 Unable to detect applicable device. Check to see if a compatible programming cable is used".

So I did the mod (wire link between black and brown wires) and the A cable worked perfect.

I originally tried 2 laptops (one running XP and the other Vista) but got the same error message.

I'm not sure why Gary and several others had no problem using the A cable to program generation 2 radios.

One idea - maybe later production runs of the A cable already had the mod done at the factory but then Motorola decided to call it a B cable. So later production A cables work with gen 2 radios while earlier production A cables don't work???

Anyway, it looks like I took a risk trying my unmodded A cable!!!!

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sat Nov 08, 2014 9:58 am
by com501
The A cable just won't work, it doesn't damage the portable. On the mobile they moved the grounds around, and depending on how the mobile is powered and how that ground is shared with the computer you are using, it can be a disaster. The portable, on the other hand, has such a low risk of sharing a ground with your computer while you are programming (most people DON'T buy the RF adapter or run the portable from a bench supply with a common ground to the computer) that it is not a risk.

All in all, a completely stupid engineering decision that can cause havoc in a small percentage of cases, and a poorly thought out one. At the very least, programming cables (IMHO) should be backwards compatible but they should NEVER EVER be capable of damaging a previous version of the same radio series.

You can flog Motorola for this one.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sat Nov 08, 2014 10:57 am
by g8tzl2004
You would have thought that Motorola would have provided free replacement cables - which probably cost $2 to manufacture in China...seriously!!!

So far 3 different users have told me that they used the portable A cable on generation 2 radios with no problems....I'm not sure why they worked?

OK on the mobile cable - fortunately I have an original rear accessory B cable...but its just a straight thru cable with no level conversion so its possible to easily home brew one!!!!

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sat Nov 08, 2014 8:39 pm
by com501
I've always used the front GCAI cable for programming, mostly because it is the same cable I use for XTL mobiles. Remember that you have to power cycle the mobile if you go from front to rear USB for programming or other uses. It can't seem to figure out whats going on and disables the front connector, or vice versa.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Sun Nov 09, 2014 9:52 am
by g8tzl2004
Thanks for the info...my XTL rear prog socket is, of course, different from the XPR rear socket so I had to buy two cables...although I got a real new Moto rear XTL prog cable for $8 which was very reasonable. I think the XPR mobile prog cable cost $27 ....I was almost tempted to build my own..old USB lead (free) + $5 for rear accessory plug...BUT get the GND correct!!!

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Fri Nov 21, 2014 11:28 am
by wavetar
g8tzl2004 wrote: So far 3 different users have told me that they used the portable A cable on generation 2 radios with no problems....I'm not sure why they worked?
I have seen an unmodified cable work on a Gen 2 portable. It's a floating ground at that point...so it's a crapshoot as to whether it'll work or not, with high odds on it not working. If that ground value floats close enough to actual ground, it'll work.
g8tzl2004 wrote: OK on the mobile cable - fortunately I have an original rear accessory B cable...but its just a straight thru cable with no level conversion so its possible to easily home brew one!!!!
We've made many of our own with shielded cable for use with TRBOnet/NeoNytro or other data software. If you use the standard unshielded programming cable, RF can leak in and completely lock up the computer USB ports, causing you to need to reboot the computer to get them back. Common issue, so much so that most of the major TRBO data software providers make & sell either shielded versions of the cable, or use RF chokes on them to mitigate the issue.

Re: XPR6550 Prog Cable for XPR7550 - is it safe?

Posted: Fri Nov 21, 2014 2:07 pm
by g8tzl2004
OK on the floating GND - thanks.

I guess the trick is to buy a cheap A cable and do the simple mod to convert it to a B cable

OK on using shielded cable when homebrewing a mobile trbo prog cables