Nautical VHF radio from Raymarine type 49e, Tx ok but no Rx.
Understand a possible cause might be linked to bad ceramic filters
I've located two ceramic filters marked "CQ M50FW".
Need help to find any information for replacement, as manufacturer,
data sheet, possible replacements type, etc.
Thanks

On Monday, October 24, 2016 at 9:39:50 AM UTC-4, wrote:
Nautical VHF radio from Raymarine type 49e, Tx ok but no Rx.
Understand a possible cause might be linked to bad ceramic filters
I've located two ceramic filters marked "CQ M50FW".
Need help to find any information for replacement, as manufacturer,
data sheet, possible replacements type, etc.
Thanks

These?

https://www.aliexpress.com/store/pro...979023900.html


Peter Wieck
Melrose Park, PA

On 24/10/2016 14:39, wrote:
Nautical VHF radio from Raymarine type 49e, Tx ok but no Rx.
Understand a possible cause might be linked to bad ceramic filters
I've located two ceramic filters marked "CQ M50FW".
Need help to find any information for replacement, as manufacturer,
data sheet, possible replacements type, etc.
Thanks


Any coloured dots on them?
Coincidence I just replaced a 10.7M one this afternoon, as easier than
hooking up an RF oscillator to test if failed FM receiver. Unfortunately
not the silver migration, ohmic problem ,something else around an LA1186
FM front end, all DC are correct by the schematic.

On 24/10/2016 16:33, N_Cook wrote:
On 24/10/2016 14:39, wrote:
Nautical VHF radio from Raymarine type 49e, Tx ok but no Rx.
Understand a possible cause might be linked to bad ceramic filters
I've located two ceramic filters marked "CQ M50FW".
Need help to find any information for replacement, as manufacturer,
data sheet, possible replacements type, etc.
Thanks


Any coloured dots on them?
Coincidence I just replaced a 10.7M one this afternoon, as easier than
hooking up an RF oscillator to test if failed FM receiver. Unfortunately
not the silver migration, ohmic problem ,something else around an LA1186
FM front end, all DC are correct by the schematic.

In my case it was failed 20 yearold solder at one of those large wire
1.5 turn air cored inductors, presumably from heatsinking of the
original PbSn soldering

On Mon, 24 Oct 2016, wrote:

Nautical VHF radio from Raymarine type 49e, Tx ok but no Rx.
Understand a possible cause might be linked to bad ceramic filters
I've located two ceramic filters marked "CQ M50FW".
Need help to find any information for replacement, as manufacturer,
data sheet, possible replacements type, etc.
Thanks

Why think the ceramic filters are bad?

Inject a signal into that IF, see if it gets past the filters. To double
check, inject after the filters.

Assuming it's old enough to use crystals, why not wonder if the local
oscillator crystal (or any second conversion crystal, if there is one) is
bad or not oscillating? Have you even checked to make sure there is a
crystal for the first oscillator in the receiver?

Michael