Yaesu VR5000

[llonen]

I have had this radio in the workshop for some time now and am getting no-where with it. Customer reported complete loss of receive, when asked it was working one day and the next no receive. I was able to obtain part of a service manual which is little more than some pdfs of board layout, block diagram and circuit diagrams, none of these are searchable.

Connecting this to a sig generator confirms the radio is completely deaf, I mean nothing, nada with a starting signal of 5uv upwards, I have checked this across the five bands this scanner covers and same result. Everything else on the radio works fine display, menu's buttons etc.

Does anyone have a more complete service / technical manual for this radio, and any ideas where to start a (list of voltages and test points would be useful). I would post pics but there is nothing obvious to note on the boards just a pile of smd stuff.

Thanking you all in advance

[CapLeaker]

Re: Yaesu VR5000

What do you mean exactly by deaf? No static noise either? Go spray some rf right into the last IF filter with your sig geni. You should hear something, since it is the last conversion stage. That bypasses a lot of things.
If you heave a totally dead receiver, no noise, nothing coming from the speaker, then I’d say there is something stuck in the headphone jack, the audio ic is bad, the mute jack is shorted, or the PLL is unlocked. The lock and unlock voltages and points are in the schematic.

[llonen]

Re: Yaesu VR5000

Sorry my mistake, when I mean completely deaf there is simply no received rf signal, maybe the PLL is unlocked but there is plenty of static coming the speaker just no received modulated signal irrespective of frequency block or mode. One board is the RF board and the other board is the IF board plus the control board etc. I'm not sure where to start injecting a rf signal.

I'm including scans of the block diagram to kick off.

[CapLeaker]

Re: Yaesu VR5000

as long as you got static coming out, the PLL is locked. An unlocked PLL acts like a squelch set up high, mute button pressed etc.

Maybe one of the IF amplifiers is dead? I had that happening on a TS-450SAT.
did you check both antenna inputs?

[llonen]

Re: Yaesu VR5000

Nods, I checked both antenna inputs there is no difference between them. Thanks for the pdf, looks like there are some voltages on there to check and additionally I was able to find an alignment guide for this radio. There are some basic test points there to look at, not that I am looking to align the radio but there are some checks there that will confirm some of whats working and not.

Will keep you updated

Kind regards

[CapLeaker]

Re: Yaesu VR5000

Same thing happening on the main and sub VFO? Does the S meter do anything? Look at the first schematic on the left (scroll towards the bottom) there are test voltages for locked, unlocked and mute.

[llonen]

Re: Yaesu VR5000

To date the same thing happens with the main and sub vfo, nothing shows on the S meter.

[CapLeaker]

Re: Yaesu VR5000

go to the IF filter and spray some RF from a frequency generator in it. this way you can tell where roughly the problem is.

[llonen]

Re: Yaesu VR5000

Now when you say spray some RF in, are you on about using something like an RF probe but in reverse

[CapLeaker]

Re: Yaesu VR5000

I just use an open ended piece of RG-58 coax.

[Ruggero]

Hi everybody,
I have the same problem.
After few minutes or sometimes a little bit more,
suddenly the signal disppear.
If i touch some components of PLL circuit with the Point of a screwdriver, or if i use a fan to refresh some components the signal come back again.
Probably the screwdriver or the temperature change modify some capacity value or insert RF noise and the PLL start again.
IIonen did you find any solution?
Where is the IF filter on the scheme?
Thanks so much
Ruggero