The PHILCO Phorum

Hi everyone; I'm a new member to this site and I have a problem getting a proper set of schematics (even from Riders) !!!
Example: I really liked the Philco 48-200 and I purchased a couple of them because I was looking at a Riders schematic and it has some really good troubleshooting specs. What I didn't realize was that the schematic and the troubleshooting guide is for the 48-200 Code 125 and my 2 sets are Code 121. The 35Y4 and 50L6GT are strictly for use in a Code 125 set and are replaced with a 35Z5GT and a 50A5 in a Code 121 set. Since the pins are different that means the schematics are different for the Code 125 and the Code 121.
It appears as if there are a lot more Code 121 sets in existence than there are Code 125's. So why did Riders not draw up a set of schematics for the Code 121 sets instead of just indicating the tube changes on the Code 125 schematics ???? This problem occurs on a lot of the Philco sets during the 1940's ans 50's.
Anyway I have seen a schematic of a 48-200 Code 121 (with the 35Z5 and 50A5) somewhere in the past and my other question is: where can I find the proper Philco schematics with the Code 121 ?????
Thanks;

Andy

winniefs Wrote:It appears as if there are a lot more Code 121 sets in existence than there are Code 125's. So why did Riders not draw up a set of schematics for the Code 121 sets instead of just indicating the tube changes on the Code 125 schematics ???? This problem occurs on a lot of the Philco sets during the 1940's ans 50's.
Anyway I have seen a schematic of a 48-200 Code 121 (with the 35Z5 and 50A5) somewhere in the past and my other question is: where can I find the proper Philco schematics with the Code 121 ?????
Thanks;

Andy

Hi Andy,
Rider's only printed the schematics that were submitted to them. In some cases the code change might have only been something in text. Chuck Schwark here might be the best possibility of having something that you need.

GL,
Bill

Well a 50A5 is basically a loctal version of a 50L6 so the pin out is a little different but they are electrically the same. The 35Y4 is basically the octal version of a 35Z5. It shouldn't be too difficult to sort out by using a tube manual. It's very likely that the two tube changes were the only difference they made to the circuit between the two codes, otherwise there would be more documentation, did Riders show the changes made with a sub diagram? What I find strange is why there is a code 121 and a code 125 but nothing inbetween, most have a code 121 and then a code 122 but they didn't always do that for some reason.
Regards
Arran

... and why don't they have codes 1 to 120 either?

The codes 1 to 120 were sold to Zenith, who re badged them as Waltons tombstones. That's why they are so popular.

Now you know the rest of the story.

really?

Yep.