Looking for HT1000 service brief SRN-1202D

[unleashedff248]

I need a copy of the service brief for the noise issue. I got a BN with that problem bad. It almost sounds like digital over an analog radio. Just a bunch of static.

When you use an external speaker mic you can hear some voice over the noise. When you use the internal mic you get nothing. I'm no tech, but it's a buddies radio and I figured I'd try to help out. I tried opening it up but I can't find any of these solder ground contact pads.

Anyone have a copy in PDF or other electronic version? And how would I get these brief's? Do only dealers get them?


Thanks in advance!

[Karfield]

I can't give you a copy of the SRN but I can tell you exactly what you need to do. Course as I never completely followed the print out I'd say it's not completely accurate anyway.

Step 1 is to solder the Ref Osc and VCO shields together, just 3 points is good enough, or do what I did make a fully solder line all the way across.
Step 2 Solder the shields on bottom of radio together.

What this soldering does is just create a larger ground plane for the RF to disipate through since the whole problem with the board was the lack of good grounding.

Step 3 This is actually one of the important ones. You need to change the chasis shield out to one of the newer style seperate clip shields. The largest issue with HT1000 UHF was the wearing down of the side clips causing the shield to "rub" along the ground points causing noise while the radio was in motion.

Step 4 (my personal addition) make sure the shield is nice and tight against all of the contact points. This includes the 2 on the controller board. If you have to beef them up a bit with solder go for it. It all helps.

Other note, if the butterfly clips on top of the rf board shields have not been removed angle them up a bit so they make good contact with the chasis shield and the casting.

Now keep in mind none of this will do you any good if your ref osc or PA are noisey. (and yes I saw many a noisy ref osc cause nasty tx noise in my day)

[Karfield]

Oh, wanted to post the part numbers for ya

The kit used for the SRN1202 is REX4465

If you can recover your control flex you can save a bundle just buying the shield and clips they are
2685351C01
4285350C01
4285350C02 (x2)

The kit comes with all sorts of other stuff like, replacement thermal pad, a small piece of capton tape, a shock pad but I never really used those they way they were intended. Shock pad however is great to help keep the jumper in place.

[unleashedff248]

I can't believe Moto wants over $100 for the kit...jeez.

Well forget that, I'll try it myself and if not, just buy a new one. It'd be cheaper than buying the kit.

I'll buy the shield and clips and try it out. I can't tell if the ref osc is noisy really...or can I?

It sounds like a digital transmission almost [the background noise], but when you whack the case, it dissipates for a second which led me to believe it's the ground issue.

[RFguy]

The REX4465A also comes with a new NTN7087A Control Flex (Volume controls, chan switch, the works)

Here's the SRN

SRN - 1202D
APC - 355, 402, 432,466, 511
Date: June 1997 : Up Issued 1/00
Date Extension Only
Memo To: SRN Mailing List
Deadline: Dec. 31, 2001
From: Subscribers Product Groups/Plantation, FL
Subject: Transmit Microphonics on HT1000, JT1000, MTX838, MT2000 & MTS2000 UHF Radios
Symptoms:
A small percentage of HT1000, JT1000, MTX838, MT2000, & MTS2000 UHF radios may exhibit transmit microphonics, where
one of the following occurs:
1) Popping, crackling, or snapping noise at times making audio communication
unintelligible in the receiving radio.
2) Transmitting radio may be transmitting distorted DTMF tones.
Potential Problem Radios:
HT1000, JT1000, MTX838, MT2000 & MTS2000 UHF band radios manufactured between November of 1995 through May of
1997 Serial numbers denoted by: xxxAVWxxxx to xxxAXKxxxx
HT1000 model numbers: H01RDC..., H01SDC......N
JT1000 model numbers: H01RDH..., H01SDH.....N
MTX838 model numbers: H01RDC..., H01RDD..., & H01RDH.....N
MT2000 model numbers: H01RDx...., H01SDx......N
MTS2000 model numbers: H01RDx9PW1xN or H01SDx9PW1xN
Cause:
Some of the above radios may have been manufactured with inadequate / unequal internal grounds and shield flexibility.
Required Material:
REX4465A, material in this kit is listed below.
Part Number Description
1405307X07 Kapton Tape
2605891U03 Front Shield
NTN7087A Control Flex
7505922Z01 Thermal Pad
1185821A01 Copper Tape
SRN 1202D
7505393N33 Shock Pad
Corrective Action:
Remove any solder on the RF Printed Circuit ground tab by coil L11. Remove the kapton tape from the strip, part number
1405307X07 and trim it to size approximately .3"x.2". The tape on the strip is .5" x .25" before trimming. When placing
the tape on the printed circuit board make sure there is a sufficient amount to go over the tab to insulate it from the
projection of the front shield. See figure 1.
1.
Page 1 of 3
Remove all conductive pads that may have been placed on the RF board, part numbers 7505870Z01,
7505870Z02, or 7505870Z03. (These pads were added in some radios per SRN 1202.)
2. Solder shield ME1 to ME2. See figure 2. A minimum of three solder bridges should be used. The solder should bridge the gap
between the shields but not project above the top of the shields on the PCB. Solder shields ME6 and ME7 together in the same
manner. See figure 3.
3. Inspect the surface of the PA, U105, where it rests on the casting. See figure 4. This casting surface acts as a heat sink and may
be covered by thermal grease or a thermal pad which must be removed for inspection. The exposed PA surface must be flat with
no evidence of solder build up along the entire surface. The build up will look like bumps or blisters which may cause the board to
rock. Remove any build up with a sharp blade or similar tool. Do not leave burrs. (NOTE: DO NOT REMOVE THE PA TO
PERFORM THIS STEP.)
4. If the portable was shipped with thermal grease or a thermal pad replace with the thermal pad provided in the kit, part number
7505922Z01.
5. Replace the front shield with part number 2605891U03. A new control flex, part number NTN7087A, will have to be attached
to this shield. When attaching the new shield pay special attention that the shield tabs are properly engaged into the rear casting.
The lance of the tabs should be seated into the rear casting as deeply as possible. A small screwdriver should be used to ensure
proper seating. See figure 5.
6. HT1000 ONLY: Apply a piece of copper tape, part number 1185821A01, across the silver ground contact on the control flex
and main shield. Place a shock pad, part number 7505393N33, over the copper tape above the main shield to prevent contact with
the front cover.
Parts and $45 labor is authorized by warranty. Contact your local Motorola Authorized Service Representative to arrange for this
modification. Agency Approved product should follow the guidelines for repairs and service.