Maratrac VHF with weird problem
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radiocat37
- Posts: 210
- Joined: Mon Sep 22, 2003 9:59 am
Maratrac VHF with weird problem
I have a VHF maratrac that seems to lose itself when the power is disconnected. I bought this radio with a known issue. When I turn it on for the first time none of the control respond and I have to TX or RX. I can program the radio and everything works great, turn it off and back on and things are fine with all controls responding. I disconnect power, turn back on, turn radio on and the memeory blank secenario arises. I have done some searching and cannot find any related problem. Any thoughts? I am stumped. I have the advanced control head and this is set correctly in the RSS.
Brian Griffin: Ah, if my memory serves me, this is the physics department.
Chris Griffin: That would explain all the gravity.
.
Lois: Peter, you're drunk again.
Peter: No, I'm just exhausted because I've been up all night drinking.
Chris Griffin: That would explain all the gravity.
.
Lois: Peter, you're drunk again.
Peter: No, I'm just exhausted because I've been up all night drinking.
Re: Maratrac VHF with weird problem
If the logic board is using a Dallas non-volatile RAM device, it has a battery in it that has about a 10 year life. If the battery voltage isn't high enough, the memory will fail and the radio will forget a lot of things, like all its programming. Some info (such as tuning data) is maintained in EEPROM inside the CPU, but all the mode data is kept in the external device.
Open the bottom of the radio and remove the shield over the microprocessor area of the logic board. If you see a block next to the PROM about the size of a domino (1.5 inches by 0.6 inches by about 0.4 inches tall) with the name DALLAS on it, that's probably what's wrong. They're soldered in. They can be replaced by a similar device, which will fail in another 10 years, or by a real parallel EEPROM that will outlast the radio. This problem also happens with MaxTracs and Radius mobile radios as they all use the same logic board.
Someone else had the same problem with a MaxTrac and he may have posted something about it here.
Bob M.
Open the bottom of the radio and remove the shield over the microprocessor area of the logic board. If you see a block next to the PROM about the size of a domino (1.5 inches by 0.6 inches by about 0.4 inches tall) with the name DALLAS on it, that's probably what's wrong. They're soldered in. They can be replaced by a similar device, which will fail in another 10 years, or by a real parallel EEPROM that will outlast the radio. This problem also happens with MaxTracs and Radius mobile radios as they all use the same logic board.
Someone else had the same problem with a MaxTrac and he may have posted something about it here.
Bob M.
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MP 6.7
- Posts: 109
- Joined: Mon Aug 22, 2005 11:00 am
- What radios do you own?: Spectra, Maxtracs, MT2k, GP300
Re: Maratrac VHF with weird problem
I might be the one Bob referred to. I had a Maxtrac that would give me a checksum error on powerup (long boop). Removed the Dallas chip and replaced it with a 28C16 and it was good as new.
Dale
KE7CEU
Current radios
Mobiles: 3x D43 A7 Spectras, T83 A9 Spectra, 2x KLM and 2x KLN MCS2000's, D43 Maxtrac 32ch, D35 Maxtrac 6ch modded for 896MHz receive, M33 M1225 4ch, Lowband Maratrac on 6 meters
Portables: 2x VHF GP300, VHF P110, UHF P110, VHF A7 MT2000
KE7CEU
Current radios
Mobiles: 3x D43 A7 Spectras, T83 A9 Spectra, 2x KLM and 2x KLN MCS2000's, D43 Maxtrac 32ch, D35 Maxtrac 6ch modded for 896MHz receive, M33 M1225 4ch, Lowband Maratrac on 6 meters
Portables: 2x VHF GP300, VHF P110, UHF P110, VHF A7 MT2000
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radiocat37
- Posts: 210
- Joined: Mon Sep 22, 2003 9:59 am
Re: Maratrac VHF with weird problem
Thanks for info. That is exactly what is in there. A small black box with DALLAS written on it. It looks like the 28C16 chips are pretty available on ebay. I will post back if I am successful.
Brian Griffin: Ah, if my memory serves me, this is the physics department.
Chris Griffin: That would explain all the gravity.
.
Lois: Peter, you're drunk again.
Peter: No, I'm just exhausted because I've been up all night drinking.
Chris Griffin: That would explain all the gravity.
.
Lois: Peter, you're drunk again.
Peter: No, I'm just exhausted because I've been up all night drinking.
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radiocat37
- Posts: 210
- Joined: Mon Sep 22, 2003 9:59 am
Re: Maratrac VHF with weird problem
OK....Finally got the parts, but what is the secret to getting this logic board off?? I have practically unscrewed everything but it still won't come loose where the side screws hold it to the chassis section.
Brian Griffin: Ah, if my memory serves me, this is the physics department.
Chris Griffin: That would explain all the gravity.
.
Lois: Peter, you're drunk again.
Peter: No, I'm just exhausted because I've been up all night drinking.
Chris Griffin: That would explain all the gravity.
.
Lois: Peter, you're drunk again.
Peter: No, I'm just exhausted because I've been up all night drinking.
Re: Maratrac VHF with weird problem
There are two T-8 flat-head screws holding the heat sink to the side of the chassis. These need to be removed, then the logic board will lift straight up. You may have to disconnect the connector on top of the RF board as the pins from the logic board go through the RF board. You may also have to remove the audio/squelch board to gain access to the side of the logic board, or use a right-angle Torx wrench (if you can find one).
Bob M.
Bob M.