On 08/12/2020 02:25, Easwaran Unni Tharakkal VU2TE wrote:

Dear all
My 857D not getting switched on
checked voltage up to PCB and tried after removing the brown jumper but no luck
looks for help to locate the problem
73 s and regards
VU2TE
UNNI

So you've got the head plugged in properly, and the data cable is in the right place?

You've not left a programming lead plugged in have you? And you've got 12v power going to the radio?

Checked all power and connection cables?

If you're not sure unplug it all and plug it back in again lol.

Are you sure you're pressing the right button to power it on?

What have you done to it since the last time you sucessfully powered it up?

Elwyn

Dear all
My 857D not getting switched on
checked voltage up to PCB and tried after removing the brown jumper but no luck
looks for help to locate the problem

73 s and regards

VU2TE
UNNI

The drift might have been some slight tension or dirt in the tuning knob tension assembly pulling the knob slightly. My radio mobile will change frequency with vibration of the car if the tension adjustment is off.
The display on mine doesn't show any errors on the master oscillator.
73
Ben
KB5ZO

UPDATE: The drift seems to have been a fluke. I've been monitoring several times, two hours at a time and the radio is rock solid. Even off overnight and watching for the first two hours after turn on I see zero drift. Never saw it do that 40Hz drift thing before but then I usually don't have it on the same frequency for more than a few minutes. Maybe it just didn't care for who I was listening to and wanted to "get away". As I write the thing continues to be zero drift! Yawn...

OK, will dust my oscilloscope and have a look at the FETs.

And at the same time I will order some filters, seems to be good idea to change these :)

Nice to have something to do during these dark times :)

Just was monitoring a couple QSOs on 7145.00 and noticed the display had changed to 7145.01. Thinking I may have bumped the Main dial I changed it back to .00. Several minutes later I noticed the display at 7145.04 (no QSO here now). I had never witnessed this type of "drift" with the rig before (but to be honest I had never monitored SSB for such a long duration as I use mostly CW). The rig has been on well over an hour now and no more movement in the last 15-20 minutes.
I know 40 Hz isn't the end of the world but am wondering whether I need be concerned or not. Stats: No TCXO, radio 1+ years old, used exclusively inside, otherwise never any other issues.
Do I need a TCXO? Don't do digital and no problem ever noticed on 2M or 440 (although I use those rather less; mostly use HF with this radio). Am I worrying unnecessarily? Thanks for insights! (Now another 15 minutes with no change...still on .04)

From what I can tell that is so, but the actual switching is convoluted and not at all clear to me. Download the service manual and take a look at the block diagram and read the technical discussion.?
I looked at the CF1004 signal with my scope to see that mine was working and my transmit problem seemed to be in the FET amplifier after it.
Others say it is a problem with CF 1002,3, and 5. There are evidently a lot of problems with those crystal fitters and changing them when you are in the area is suggested.
A quick check with your scope should tell you if the CF1004 is passing the signal or if you are losing it somewhere else.

So these filters are covering the AM and SSB line, but not in use in the FM line?

The service manuals are available on line and a quick search will find them.
Check the output SSB and if it is weak as well it is very likely that the SSB crystal filter is bad as it is used solely for SSB, both receive and transmit. If the AM is OK transmit and receive this would zero in on the SSB filter CF1004 that would be the most likely place to look. The AM filter CF1005 is switched into the same part of the transmit chain for AM and the same amplifier circuits are used. FM and CW do not use this part of the circuits (as well as I can determine from the block diagram and schematic.?
When you download the service manual and look at the schematic you will find these filters in the upper right hand corner. D1076 and D1078 switch between the two.
At least the CF1005 is very cheap at $0.71 from Yaesu. I don't know about the price for CF1005.?
The output of the receiver chain feeds these two filters directly for SSB and AM. The FM and CW have different paths per the block diagram.
Suggestions here are if you are having almost any problem change the CF1002, 2. and 5 filters. CF1004 gives fewer problems since it is hermetically sealed.
Anyway if you order parts get the filters:
? ? ? ? Yaesu P/N? ? ? ? ? ? ? ? ? ? ? ? ?ID? ? ? ? ? ? ? ? ? ? ? ? ?Description? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?price
1-? ? ? ? H3900543? ?$0.71? ? ? CF1002? ? ? ? ? ? CERAMIC FILTER ALFYM455E? ? ? ? ? ? ? ? ? ? ? ? ? ?$ 0.71? ? ? ? ? ?
1 -? ? ? ?H3900545? ?$0.71? ? ? CF1003? ? ? ? ? ? CERAMIC FILTER ALFYM455G? ? ? ? ? ? ? ? ? ? ? ? ? ?$ 0.71? ? ? ? ??
1 -? ? ? ?H3900542? ? $0.71? ? ?CF1005? ? ? ? ? ? CERAMIC FILTER ALFYM455H? ? ? ? ? ? ? ? ? ? ? ? ? ?$ 0.71? ? ? ? ??
Just so that you will know not everyone would agree with me on this.

开云体育

Hi

Just bought a used FT 857, and have discovered that the SSB receiver seems to have at least 40 dB attenuation or what ever it is. I can hardly hear any stations, and S-meter shows low value.
If I change to FM everything works excellent. I do not know the state of the TX, as I am not able to do any communication.

Listening to the weak signal in SSB mode, the same signal is very high when changing to FM

Anyone who knows what this could be?
And where do I get the repair manuals?

Thanks in advance

Ruben

Thanks very much for the update. This kind of information can be very valuable.

For archiving purposes, I fixed the rig replacing the D3053 (V/U switching diode). Thanks everybody for the help

I believe your best bet would be mixing signal from another antenna (tuned to another frequency) with inverted phase, like the X-phase does for QRM

Not with the 857. Only one receiver is actually receiving at any time.
--
Leonard K. Pennock (AD7AS)

I'm not sure where to post this question, so apologies if it is too far off topic for this group:

Is it possible to remove static crashes due to lightning from radio reception by the following method ?

It's not, see me last message

开云体育

开云体育

Another easy way to test is to let your rig become “cold”....say, below 0degreesF as in a mobile installation on a winter day. On 2m/440 FM the temp-related frequency drift in the master oscillator will cause the rig to be off frequency. Possibly close enough to key up a sensitive repeater... but your transmitted audio will be somewhat garbled. (Sounding like it would if you were accidentally up/down the 5kHz on the preset)

Replaced the filter and didn't solve the problem.

I noticed something: During a repeater transmission with low RX, briefly hitting the PTT restore the full RX signal

Looks like a relay issue, but where to start?