[Premium-Rx] Eddystone 1650-3 , with text

[GandalfG8 at aol.com]

Hi Peter
 
As Dan commented earlier, and he's definitely one of the experts when  it 
comes to repairing corroded CPU boards, there's a good possibility  of more 
damage than might seem obvious to start with, and  thorough cleaning as he 
suggested followed by point to point checks, with  repairs as necessary until 
the PCB at least is all as it should be, is really  your only option if you 
want to avoid even more problems in the future.
 
It's a while since I worked on a 1650 CPU board, and that was a 1650/9  
which is different to the earlier models, and I can't recall now which ICs were 
 socketed and which soldered directly to the PCB, but if there's any 
indications  of damage beneath ICs or sockets, and really even if there isn't, you 
need to  remove them to check and make good.
The only problem with that is that it's also quite easy to do even more  
damage just by removing them if you haven't got the right tools, but if you  
don't you could just be storing up more trouble for later...catch  22 
unfortunately.
 
The 1650 service manuals do provide all the circuit information you need  
but some of their alignment instructions leave quite a lot to be desired,  
and I've found that some models of a given version might, in some respects at  
least, be better matched by other manual versions than their own, which  
can be quite frustrating at times.
 
As far as I'm aware, the actual schematic of the CPU board should be the  
same,  or very close at least, for all versions prior to the 1650/9, at  
which point the processor switched from a 6802 to a 6809 and with larger Eproms, 
 so what you've got should match your 1650/7 manual.
 
I don't know if it will help but I've posted a single file to Rapidshare  
containg the manuals for the original 1650, the 1650/6, quite an oddball that 
 one, the 1650/7 that you've already got, and the 1650/9, just in case 
there's  anything in there that might prove useful.....
 
_http://rapidshare.com/files/2655834510/Eddystone_1650_Manuals.zip_ 
(http://rapidshare.com/files/2655834510/Eddystone_1650_Manuals.zip) 
 
Good Luck
 
Nigel
GM8PZR
 
 
 
 
 
 
In a message dated 23/03/2013 21:09:13 GMT Standard Time, zpz at gmx.de  
writes:

Hello  all,

I try to repair an Eddystone 1650-3. It has the  SSB-display.
The trouble was first that it first showed nothing usefull and  did not 
react to the power button. The owner then replaced the leaked battery.  The 
acid had derogated the cpu-board, even some of the ceramic capacitors lost  
parts of their housing. The solder points were extremely hard to solder  
again... Measuring conductance of the circuit pathes requires to push the tips  
very hard into the old solder, to get any response.
Now I replaced the bad  ceramics and the tantals on the cpu-board and all 
of the Philips 035 series  electrolytics of the front assembly. As expected, 
the most were bad - the  capacity losses were between 30 and 80 percent.
Now, the receiver does  still almost *nothing* - there is no reaction of 
the power button and no  sound; only some LEDs of the SSB-display are showing 
activity.

I  measured the voltage on the cpu-board behind the 7805, it is 4.88V. The 
next  idea is to check if there is any activity at the cpu and then the to 
have a  look at the little regulator on the display board, but I am a bit 
discouraged,  because it is difficult to access all the parts. I do have the sm 
of the  1650-7 but it seems to be not very helpfull.

If anybody has further  ideas, that would be great.

Best regards,
Peter

ps: I am away  for some days, so my answer can be  delayed.