17 January 2009

Yaesu FRG-8800 repair

Lately I spend most of my hobby time fixing rigs for other people. But this time I have fixed a rig for my collection. It is a Yaesu FRG-8800 receiver which suppossedly came with the VHF converter...

When I got it, I found a surprise. It is a heavily modified unit (called Broadcast Monitor Receiver 2) and there is NO VHF converter, but an extra module with balanced audio and IF output on its place, along some other PCBs and other internal mods. You can check what I am talking about here:

This is the company:

http://www.surreyelectronics.com/

This is the mod leaflet front page:

http://www.surreyelectronics.com/leaflets/Receiver2F.jpg

And this is the rear page:

http://www.surreyelectronics.com/leaflets/Receiver2R.jpg

Here you have some pictures:





Well, I knew it was in unworking condition and, really, it didn't work on arrival. No surprise here. I took the covers out to find some oxide in metal cans but mostly a clean receiver. This is the top side:


I polished the cans, dusted it out and started troubleshooting.

AM sort of worked but SSB was completely deaf. While turning the unit to check lower side, I heard some noise inside... and it was a lose piece of PCB!!!. I found it was a PCB corner and it had a trace on it... could this be the cause of the SSB deafness?. I fixed it by glueing and bridging it:




So I put back the PCB, hoping for the best... and no, it was WORSE!!!. Now AM was received faintly and SSB needed about 0.2V to be heard. So I went back to head scratching until I found that pulling the PCB a bit generated some better reception. So I decided to completely remove it:


I took some detailed pictures of the added PCBs:





As you can see, there are a couple IF filters in one PCB, a couple relays in another one and, I guess, a new detector on the third. The mods seem somewhat complex; I guess they are worth more than I have paid for the unit :-)

Looking closely I located the problem. There was another crack in a PCB corner.


I fixed it as follows, scrapping and adding some wire and solder on each crack:



Putting the PCB back got me a pretty hot working receiver :-)!!!. Here you have a very small video (sorry about the lousy quality):

video

So I decided it was time to clean the unit, removing knobs to clean them sepparately. I also replaced the four display light bulbs, as there was one bad, one dim and two with too much brightness. I put four new lamps.

Here you have some pictures of the cleaned unit, ready for alignment:





Alignment was mostly OK, just some Hertzs out in some oscillators. I used my GPS reference to be sure alignment was done OK.

And this is the result: a perfectly working receiver:



Success!!!

16 comments:

Anonymous said...

now it is time to build or buy a downconverter to 12 khz if .... feed this in your soundcard and receive some drm stations

David said...

Hi, I have recently bought a FGR-8800 that is in good condition.
The VFO knob doesn't spin as freely as it should. Do you know how to remove the knob? Cheers, David.

Jose EB5AGV said...

Hi David,

You need to remove the rubber band over the knob and then you will find a hole with the knob screw on it. You need an hex key for it, I think it is a 1.5mm one.

73 JOSE EB5AGV

Anonymous said...

Hi Jose EB5AGV.
WHAT A FANTASTIC WORKSHOP.

I have a FRG-8800 .
PROBLEM WITH REPLACEMENT ON IC,S

Radio receiver drops out and flashes on/off cycle 1 sec.on dial
Is this PLL problem .
Can you please help this is intermittent fault .
Many thanks. Garnett (zs5zt )

Evergreen Advisors said...

I turned on my 8800 this morning and it was (nearly) dead! First time I've had any problems. The receiver powers up, but no numbers are displayed and all inputs are dead (keypad, mode buttons, etc.). Any ideas about what caused this? The radio has not been moved or adjusted in any way prior to this happening. Thanks for any thoughts,

Chris KB1RXA cday@evergreenadvisors.us

Jose EB5AGV said...

Hello Chris,

It seems to me as a CPU locked up. I am not sure if this rig has a Lithium cell. If so, I would guess it is depleted and needs replacement.

If not, you need to check if CPU is running, as an starting point.

73 JOSE EB5AGV

John said...

Please help, i bought a FRG-8800 and the VHF module that is in perfect working order does not work with the radio, we have etste the module on another frg-8800 and the module is working, as wsoon as i plug the module into my radion the frg does not recocnise the vhf frequencies at all , please hlp depserate - marius@wheelchairs.co.za

Anonymous said...

Hi, I have a FRG-8800 Yaesu Communications Receiever and after I turn the receiver on the receiver automatically turns off after a few minutes. What could be causing the problem?

Anonymous said...

Good Information.
I have a FRG 8800 that works great except when it was manufactured it only covers the 2Mhz to 30Mhz range on Hf.
Any info on extending its range would be great

Thanks
john

FT said...

Hello OM José,

I have also a FRG 8800. When I started the receiver after a while the display starts flashing and there is no sound. Sometimes the flashing stops after a few minutes but its also possible that the flashing don't stop.

I'm not technical. I know the diverance between a resistor and a tomato and that's it. Do you have an idea what the problem is, please. Then I can ask somebody to help me with the repair.

Thank you in advance.

Frank (Netherlands)

Ernst said...

I am located in Melbourne Australia and I have a FRG 8800 with HF converted all in perfect condition.

Is anyone interested in buying it?

Anonymous said...

This comment is for those who have blank or flashing FRG-8800 displays. It is extracted from my note in November, 2006 QST magazine. 73, Paul, W8TM


The first failure involved a flashing frequency display in addition to no receiver audio. This was caused by a dirty trimmer TC01 in a shield box on the PLL circuit board, accessible by removing the top cover of the receiver. The service manual specification for TC01 after warmup is 18 MHz (within 20 Hz) at nearby test point TP14. Lacking a counter, I found it adequate simply to return the cleaned trimmer approximately to its original position and to verify the result by tuning WWV in a sideband mode.

The second failure was more complete: no audio and no information on the lighted display. This was caused by a dirty trimmer TC02, in another shield box on the PLL circuit board. Similar application of contact cleaner and trimmer wiggling brought the receiver instantly back to life. The service manual specification for TC02 adjustment is 5.996544 MHz at nearby test point TP09. Alternatively, I checked the receiver's clock display over time to verify reasonable adjustment of TC02 after cleaning.

Anonymous said...

I see someone asks how to remove the main knob.. I havent seen one with a grub screw or similar holding the knob on, the ones ive repaired just prise off ( they are tight) then I sat it on its end (front facing up) and put a little light machine oil ( or electrical lube) on the pot shaft and let it run down to lube the vfo, then replace the knob.spins much better after this has been done.cheers ZL2AR

Anonymous said...

Hi José,
I have a FRG8800 with no sound ,no display and after open it i see the r 108 resistor near J13 becomes hot after power on and limit to desolder.
Do you have an idea
Regards
Raymond

Anonymous said...

Hi josé,
I have a FRG8800 with no sound and no display.
After open it i see the wond resistance name R108 near J13 becomes very hot near blowing.
Could you help me.
Regards
Raymond

Iwillreviewyou said...

Kindly let me know where I can find parts for this receiver.

H. K. Al Fadhel