FW: [Yaesu-FT-101] Deaf FT101Z
|
First thing to do is get a little spray can of DeOxit. Turn the radio on it’s back with the front panel up. Hold a rag near the attenuator switch assembly to stop any over spray on?the outside of the panel.?
Flip the switch up all the way to max attenuation and gently push the spray nozzle tube into the little space under the toggle and give it a little shot of the DeOxit. There is a small rectangular felt gasket under the panel the toggle bat passes through and you can get a little shot of DeOxit solvent past it into the switch mechanism. ? Then flip the ATT switch up and down a half dozen times or so.? Now do the same thing with the spray nozzle tube but with the toggle switch all the way down.. repeat the single spray shot and flip the switch up and down a half dozen times. ?? If the contacts are dirty in that switch it wipes out all the radio’s receive signal.? If this does nothing for you problem then move on to other issues. One of which could still be a bad ATT switch!! |
开云体育Thanks Bruce for quick response to my request for help.? Never seen Deoxit for sale here in t he UK although I have seen it mentioned elsewhere.? I will have a look for some.? Sorting switch must be better than digging out FETs etc! ? Al GM4ENF ? Sent from for Windows ? From: Bruce Collins
Sent: 20 October 2021 18:30 To: [email protected] Subject: Re: FW: [Yaesu-FT-101] Deaf FT101Z ? First thing to do is get a little spray can of DeOxit. Turn the radio on it’s back with the front panel up. Hold a rag near the attenuator switch assembly to stop any over spray on?the outside of the panel.? ? |
|
I’m learning thanks men; and I have that spray for guitar audio etc there are several types available now too.
It’s contact spray that should not harm plastic. I can’t wait to start my check out of my FT101 I’ll detail my results as fall sets in up in central Ontario and winter wonderland starts again…. Plus I need a heater for the shack. 73 David VE3DPC |
|
Thanks so far.? I have cleaned and verified that the Attenuation switch is clean and working as it should.? Further research inside the equipment and the internet I find that the RF board in my FT101Z is not the one detailed in the handbook which came with the equipment.? The handbook has circuit etc for RF Board PB1960A while the installed board is PB2154.? I have searched the internet to find the circuit diagram for PB2154 without success.? Without this I am to a great extent working blind.? If anyone has a circuit for 'my' board I would appreciate a copy ( the workshop manual I have found refers to 'my' board but has no circuit)? Also any further ideas of where the fault may be would be appreciated.? Thanks again.? Alistair GM4ENF
|
|
The marker generator works but at a low level across all bands although maybe louder on some - it will not move the S meter but is clearly audible and fades out when RF gain is turned fully anticlockwise.? So long since I repaired any radio gear I have forgotten just about everything - like trying to find out where the marker loses its 'power'.? I was of the opinion that an RF device has gone open - like the 3SK51-3 or the J310 - but I may be going down the wrong track there.? The significant parts to me are:? One day it was perfect, next day on switch on it was completely different with no 'strong' signals and S meter not moving.? Transmit works fine and delivers full power.? A few days ago while using radio on air I had a loud 'crack' in the phones and signal strength returned to normal - but only for a few seconds!? I am very fond of the FT101Z and would really like to get to the bottom of this.? thanks again for? input.
|
|
Yes, that really sounds like a bad solder joint somewhere. Whether it is on the RF board ormot is another matter but since the marker is weak and so is the received antenna signals... I'd get the schematic out and follow where the marker generator signal is injected into the receiver front end!? On Mon, Nov 1, 2021 at 3:54 PM Alistair GM4ENF via <alistairfyffe=[email protected]> wrote: The marker generator works but at a low level across all bands although maybe louder on some - it will not move the S meter but is clearly audible and fades out when RF gain is turned fully anticlockwise.? So long since I repaired any radio gear I have forgotten just about everything - like trying to find out where the marker loses its 'power'.? I was of the opinion that an RF device has gone open - like the 3SK51-3 or the J310 - but I may be going down the wrong track there.? The significant parts to me are:? One day it was perfect, next day on switch on it was completely different with no 'strong' signals and S meter not moving.? Transmit works fine and delivers full power.? A few days ago while using radio on air I had a loud 'crack' in the phones and signal strength returned to normal - but only for a few seconds!? I am very fond of the FT101Z and would really like to get to the bottom of this.? thanks again for? input. |
|
Thanks Bruce.? From? the main circuit diagram the antenna signal wends it's way from the SO239 to AGC switch <already checked this is OK> to an inert tuned circuit (L01/C07)<'9mhz trap'> on the Local Oscillator board and then to Pin 3 on the RF Board 2154.? If Yaesu had tried harder they could have crammed more components onto these boards!? Tracing the actual signal path is not so easy on the hardware...? The local oscillator signal appears to meet the incoming signal at the input to the tuned circuit on the Local Oscillator board.? As both the local oscillator signal and received signals are both present but low strength it would appear to me (but as an 'amateur' I stand to be corrected!) that the fault is on the RF board or possibly the IF board.? I have 'examined' both sides of the RF board under 10x magnification for any obvious fault or deterioration - and 'touched' the components - and can find nothing unusual.? I am not quite driven mad yet but....? Thanks again - great to talk to somebody who knows stuff!? Alistair GM4ENF.
|
|
OK Keep in mind that for the most part, ?the marker generator is strong enough to be used as a built in RF generator. Great for tracing signals.? Most rigs will see about an S9 +5dB to +15dB on the S meter on every band! If you have a decent O’Scope or RF voltmeter, ?pick a low impedance test spot from the marker generator, like the emitter follower buffer stage and measure the output and use that value as a guide as you progress to though the circuit and into the RF board.? You might just have a lousy Q1 dual gate mosfet.? On Tue, Nov 2, 2021 at 2:20 PM Alistair GM4ENF via <alistairfyffe=[email protected]> wrote: Thanks Bruce.? From? the main circuit diagram the antenna signal wends it's way from the SO239 to AGC switch <already checked this is OK> to an inert tuned circuit (L01/C07)<'9mhz trap'> on the Local Oscillator board and then to Pin 3 on the RF Board 2154.? If Yaesu had tried harder they could have crammed more components onto these boards!? Tracing the actual signal path is not so easy on the hardware...? The local oscillator signal appears to meet the incoming signal at the input to the tuned circuit on the Local Oscillator board.? As both the local oscillator signal and received signals are both present but low strength it would appear to me (but as an 'amateur' I stand to be corrected!) that the fault is on the RF board or possibly the IF board.? I have 'examined' both sides of the RF board under 10x magnification for any obvious fault or deterioration - and 'touched' the components - and can find nothing unusual.? I am not quite driven mad yet but....? Thanks again - great to talk to somebody who knows stuff!? Alistair GM4ENF. |
|
Ah... here we have a? sticking point - I do not have an oscilloscope and only a fairly basic home made RF probe for my digital meter.? Although I understand the various circuit diagrams and the function of the components - and have repaired lots of old <thermionic tube> gear in the past - I don't think I would know what I was looking for here - that is unless my RF probe and Digital meter will show increase or absence of a signal.? I haver just made an extender board for the PB2154 so I can see what I might be doing(!) and will? see what I can do over the next day or so.
|
Bruce Collins
Alistair GM4ENF
