question on the visar radio

kb9suy · Post by **kb9suy** » Mon Feb 04, 2002 3:13 pm

What are the plagued problems with the visar's with the front board. My radio was bumped of my belt and it has been locking up and giving me wierd letters and numbers on my display. know I went over it with a soldering iron know it works but it gives a low battery alert when the batterys charged and the green recieve lite stays lit permently. Also can i swap front boards off 800 mhz radios or are they type specific. Or how much do they run for on a average. thanks, Lee

watertooth · Post by **watertooth** » Mon Mar 18, 2002 10:38 pm

Hi Lee, I have several Visar UHF radios with the same symptoms. Some people say "change the ribbon cable" while others say "go look for cold solder joints and PC cracks". It is a common problem that I have not heard much about. As for the low battery indicator problem, its probably a microscopic fragment of solder on the controller making trouble.
As for as I know, there is no way to use an 800 or 900 meg visar controller in your UHF rig. Good luck,
Elliot

Post by **wavetar** » Tue Mar 19, 2002 4:25 am

The problems with the Visar radio have been covered here many times. The main trouble with them is the fact that the controller board is an 8-layer board, and is far too flexible for it's own good. Over time, or with a couple of drops, the board will flex to the point of having component leads lift off the board, a real pain if it's underneath an OMPAC IC. Even worse, the traces in the hidden layers can break, rendering the board unrepairable. This happens a lot, giving the dreaded "88" or other wierd characters on the display. You MIGHT be able to swap 800MHz controller boards (NTN7404) for VHF/UHF ones (NTN7402). The EEPROM (U703)on the 800MHz board must be removed, as well as R753, and C758. These are the only hardware differences I can find between the two, all other components are identical. Whether or not you could ram a VHF/UHF codeplug down it's throat with HT1000 LAB is another story, I have no idea.

Todd

<font size=-1>[ This Message was edited by: wavetar on 2002-03-19 07:26 ]</font>

jim · Post by **jim** » Tue Mar 19, 2002 6:41 am

Did you check and see if you accidentally bridged anything while resoldering?

RadioSouth · Post by **RadioSouth** » Tue Mar 19, 2002 10:51 am

They're so trouble prone Motorola does not even have a flat rate repair available.
(Time & parts repair only). A lot of MSS will
not even attempt- they'll depot it.

Post by **wavetar** » Tue Mar 19, 2002 4:44 pm

It's not like the Depots are repair gurus, 9 times out of 10, if we can't fix it, neither can they. They just simply have the modules on hand to swap out, for a lot less money than we can purchase them for. Not much choice but to do the flat-rate at that point.

Todd