Service Manual for 900Mhz Maxtrac

This forum is for the discussions targeted at converting various models of Motorola equipment to operate in the 900MHz Amateur Band.

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ns0w
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Joined: Thu Jan 06, 2005 3:37 pm

Service Manual for 900Mhz Maxtrac

Post by ns0w »

I am looking for a Maxtrac 900Mhz service manual to buy - Motorola no longer has it available for sale - or so I was told by a number of dealers. Thanks ..
WB6DGN
Posts: 252
Joined: Fri Feb 11, 2005 5:34 pm

MaxTrac 900 Manual

Post by WB6DGN »

What do you need? I have a Maxtrac 900 manual, but not to sell. I could copy some pages and send them by either email or snail mail if you wish. The manual I have is 68P02977G10-C. You'll be dissapointed on how little useful information is in this manual. There are parts lists, schematics and the like, but no tuning info, etc. Let me know what you need and how to get it to you. I'll try to help.

73 Tom KB5DPE

(kb5dpe@arrl.net)
WB6DGN
Posts: 252
Joined: Fri Feb 11, 2005 5:34 pm

Maxtrac 900 Manual

Post by WB6DGN »

I'll also try to confirm whether the manual is available or not. If it is, will give price and availability.

Tom KB5DPE
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kcbooboo
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Post by kcbooboo »

I also tried to order one a few weeks ago and the part number shown above was discontinued and there was no replacement. The person on the phone even checked with parts ID and reported the manual is really no longer available.

Bob M.
ns0w
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Joined: Thu Jan 06, 2005 3:37 pm

Post by ns0w »

Hi Tom,

Thanks for your reply - I appreciate it. From your description is sounds that the 900Mhz manual contains more or less the same stuff that is in the VHF-800 manual which I have. I wanted the manual for 3 reasons: 1) Tuning up the radio - I notice the power output varies depending on the frequencies I use. I am also unsure about the deviation, power calibration etc. in the RSS - but it seems I will need an RSS manual for that. 2) I have an audio problem on two of the converted radios - on RX I have background noise which sounds like the other person is mobile and on the second I have something that sounds like a typical audio feedback squeal when I crank up the volume. 3) Location of components to do the audio mods described on Batlabs. 4) To protect my investment - like any good ham - :-)

I will contact you direct via e-mail to talk about the manual.

Thanks - Sebastian - NS0W
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Max-trac
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Post by Max-trac »

The 900 is a little different in the way you do a complete calibration.
It is covered in the standard maxtrac RSS manual, but you have to have the 900 manual to locate the voltage check point,
It is stupid you have to BOTH manuals.

We can help you thru it with out having to find a manual.

It sounds like you have a VCO problem.
Does it look like someone opened the VCO can????
ns0w
Posts: 5
Joined: Thu Jan 06, 2005 3:37 pm

Post by ns0w »

Thanks, once again, for the response!

Sounds like I would need a RSS manual for the calibration. I have done the first step (F2) in the calibration i.e. set temp, vdiode and the 9.6 voltage but I have no idea about the rest - F3 - through F8 on the menu. The one that concerns me a little is the deviation - not sure if there is anything else that is important.

The VCO has been opened - I opened it myself to modify the two pads to get the radio to RX and TX on 907.5. It is very possible that I have damaged it - and if that is true and this is the source of the noise then I will just salvage my filters and toss the board. Is there an easy way to confirm that I messed up the board? I have successfully used this VCO mod procedure on 4 other boards with no ill (or noise) effects, but I have also swapped the noisy board out on various radios and the noise seems to follow the VCO board.

73 de NS0W
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