Sanyo RP 8880 - UK Vintage Radio Repair and Restoration Discussion Forum

agardiner · 29th Mar 2023, 3:00 pm

Hi All,

So I have had 4 of these complex world band sets in recently; all of them with exactly the same list of faults. There are also some on ebay listed with the same issues, so I thought it might be useful to share the repairs required.

The fault are as follows, listed in the order you will find them if you work through each one in turn.....

No radio at all, just a low level hum from the speaker. No FM reception. No AM reception. No SW reception. Low RF gain on all bands. Generally poor performance.

You should start by ensuring you have the service manual, as they are complex to disassemble and also to align. Once the chassis is removed from the cabinet, you are going to need to remove the PCB from it. To do this, you first need to 'clamp' the 3 tuning wheels to the chassis using a self tapping screw, see photo for example. Then you can undo the bolt that secures the tuning wheel to the appropriate capacitor, unplug all the various cables and then unclip the PCB from the plastic chassis. As this is tricky and takes time, it pays to then carry out all the repairs I now list regardless of whether your set needs every one of them.

1) All switches and controls should be given a good dose of contact cleaner. The phono/radio switch on the rear is the cause of no radio at all.
2) Replace oscillator transistors - Q103 - FM, Q112 - AM, Q108 & Q111 - SW. These can all be replaced with type 2N2222A, but note the pin outs are different. This cures the bands all being dead.
3) Replace RF amp fets - Q101 - FM, Q105 - AM, Q106 & Q109 - SW and the dual gate mixer Q107. 2N3819 types are suitable but again with different pin outs. Use a 3N201 for the dual gate mixer which drops straight in. This cures the poor RF gain.
4) You now need to re-align the IF stages. The unit employs ceramic filters which drift slightly over time, so the IF needs tweaking to peak it back to the ceramic filters frequency. No need to replace the filters. This cures the generally poor performance.

I haven't found a need to replace capacitors in one of these and I have not had problems with the BFO. One the above has all been carried, you will probably have a fully working and interesting set. Good luck!

GLENZ32 · 20th Apr 2023, 2:02 am

Thanks for sharing this useful information. It sure does look like a bit of a jigsaw puzzle to get apart. Reminds me of the National/Panasonic model equivalent from the same period. Nice work!

Silicon · 20th Apr 2023, 5:20 pm

Have you come to any conclusion as to why so many transistors are faulty?

Is it easy to put the batteries in the wrong way?

agardiner · 22nd Apr 2023, 9:33 am

None of the transistors had junction shorts. They were all low gain though, which seems to be becoming a common age issue. It may be that you don't need to change every transistor, but given the complexity of disassembly, it is better to just change them all to ensure future reliability.

Goldieoldie · 22nd Apr 2023, 6:25 pm

Interesting the Sony icf 6800 suffers from the same problem of rf transistors going low gain .

Station X · 14th Aug 2023, 9:11 am

One post moved to a new thread here:-

https://www.vintage-radio.net/forum/...d.php?t=203089

29th Mar 2023, 3:00 pm	#1
agardiner Octode Join Date: Sep 2020 Location: Thetford, Norfolk, UK. Posts: 1,584	Sanyo RP 8880 Hi All, So I have had 4 of these complex world band sets in recently; all of them with exactly the same list of faults. There are also some on ebay listed with the same issues, so I thought it might be useful to share the repairs required. The fault are as follows, listed in the order you will find them if you work through each one in turn..... No radio at all, just a low level hum from the speaker. No FM reception. No AM reception. No SW reception. Low RF gain on all bands. Generally poor performance. You should start by ensuring you have the service manual, as they are complex to disassemble and also to align. Once the chassis is removed from the cabinet, you are going to need to remove the PCB from it. To do this, you first need to 'clamp' the 3 tuning wheels to the chassis using a self tapping screw, see photo for example. Then you can undo the bolt that secures the tuning wheel to the appropriate capacitor, unplug all the various cables and then unclip the PCB from the plastic chassis. As this is tricky and takes time, it pays to then carry out all the repairs I now list regardless of whether your set needs every one of them. 1) All switches and controls should be given a good dose of contact cleaner. The phono/radio switch on the rear is the cause of no radio at all. 2) Replace oscillator transistors - Q103 - FM, Q112 - AM, Q108 & Q111 - SW. These can all be replaced with type 2N2222A, but note the pin outs are different. This cures the bands all being dead. 3) Replace RF amp fets - Q101 - FM, Q105 - AM, Q106 & Q109 - SW and the dual gate mixer Q107. 2N3819 types are suitable but again with different pin outs. Use a 3N201 for the dual gate mixer which drops straight in. This cures the poor RF gain. 4) You now need to re-align the IF stages. The unit employs ceramic filters which drift slightly over time, so the IF needs tweaking to peak it back to the ceramic filters frequency. No need to replace the filters. This cures the generally poor performance. I haven't found a need to replace capacitors in one of these and I have not had problems with the BFO. One the above has all been carried, you will probably have a fully working and interesting set. Good luck! Attached Thumbnails __________________ Adrian. www.radiorestoration.co.uk

20th Apr 2023, 2:02 am	#2
GLENZ32 Hexode Join Date: Apr 2008 Location: Wellington, New Zealand Posts: 289	Re: Sanyo RP 8880 Thanks for sharing this useful information. It sure does look like a bit of a jigsaw puzzle to get apart. Reminds me of the National/Panasonic model equivalent from the same period. Nice work! __________________ Visit my Vintage TV & Radio Page - http://nzvintagetvradio.blogspot.com/

20th Apr 2023, 5:20 pm	#3
Silicon Octode Join Date: Jun 2007 Location: Coulsdon, London, UK. Posts: 1,993	Re: Sanyo RP 8880 Have you come to any conclusion as to why so many transistors are faulty? Is it easy to put the batteries in the wrong way?

22nd Apr 2023, 9:33 am	#4
agardiner Octode Join Date: Sep 2020 Location: Thetford, Norfolk, UK. Posts: 1,584	Re: Sanyo RP 8880 None of the transistors had junction shorts. They were all low gain though, which seems to be becoming a common age issue. It may be that you don't need to change every transistor, but given the complexity of disassembly, it is better to just change them all to ensure future reliability. __________________ Adrian. www.radiorestoration.co.uk

22nd Apr 2023, 6:25 pm	#5
Goldieoldie Octode Join Date: Jul 2014 Location: Petersfield, Hampshire, UK. Posts: 1,036	Re: Sanyo RP 8880 Interesting the Sony icf 6800 suffers from the same problem of rf transistors going low gain .

14th Aug 2023, 9:11 am	#6
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 20,636	Re: Sanyo RP 8880 One post moved to a new thread here:- https://www.vintage-radio.net/forum/...d.php?t=203089 __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.