Posts: 31
Threads: 4
Joined: Aug 2007
I relate this story because it has happened to me before, it is not always easy to notice, and can have serious consequences. I had just finished recapping a 16B chassis, one which I am very familiar with. All the tubes were checked and ready to go. It warmed up fine, but the set seemed not working right, there was some clicking type audio when changing bands, and tlow volume only when touching the second detector, but I got no IF through. A quick voltage survey showed absent voltage on the screen grid of the 77 first AF tube and plate of the 78 QAVC tube. Tracing the feeder to that point, I found the wire which runs from the 1 MEG resistor on the 5th terminal of the filter bank can had been caught under a bakelite block (compressed between the foot of the block and the chassis). After shutting down and extricating it, I could see that the insulation was crushed and the wire had shorted to the chassis!! After freeing it, the radio played like a songbird. If I had not picked up on this for a while, the power transformer may have been at risk. This was my second experience with a similar fault. Another clue was that the 80 rectifier tube had blinked briefly, with a strange light flash inside it, the first time I full powered the chassis, probably as the short developed. So one can never dodge mistakes entirely, and some of them are of our own making!
Posts: 909
Threads: 117
Joined: Jun 2007
I always "extricate" the old Philco orig bakelite blocks when electronically restoring vintage Philco & AK "coded" orig chassis components. I replace them with terminal-strips to mount new caps ( fully visable for the next tech to deal with yrs later), and therefore never have these grounding type probs. Keeping "authencity" hidden under these chassis is for the purists generally speaking? Does it really add any "value" to these sets? Does it ad probs re-building & re-installing orig bakelite cap blocks sometimes? Very glad you found the prob in your recap- restoration, and corrected it! Seems we have all learned something here all over again?
Posts: 237
Threads: 24
Joined: Dec 2007
City: Gladwin, MI
I always restuff the bakelite blocks because I like the original look on my sets. In many cases, I use Brian's (BDM) 'flip and ship' method whereby you don't even have to unsolder the connections. You just flip the block over, heat and remove the old capacitors and install new ones. In this case, it's actually faster than unsoldering all those connections and installing terminal strips.
But, to each their own, that's what makes this hobby interesting.
Regards,
Ed
Posts: 31
Threads: 4
Joined: Aug 2007
I suppose to each their own. I don't see any value in using terminal strips as opposed to the bakelite blocks. My own preference is to preserve the bakelite blocks, since they have the correct terminals already in the right places. It's harder to make a mistake using the original bakelite block IMHO. To me, that esthetic is important. I like the look of a chassis that retains originality. If function were all that were important, we wouldn't care about correct knobs, finish, grillcloth, cleaning off dirt, etc. etc. etc. Just slam bang it together any old way and listen to it. Or we could install solid state components for longer life. Lets face it, anyone can get a radio working, it takes some more skill and dedication to restore a radio. So where do you draw the line? Just because it's under the chassis doesn't mean it isn't looked at. No one much cares about antique radios except other geeks like us anyway. When I sell a radio, eventually someone will pull out the chassis, examine it and pass along the word that my work is above grade. THat keeps customers coming.
Unlike some "purists", I do not favor continuing to use the original capacitors in the blocks if they happen to test currently good. I believe they will fail at some point and they were never engineered to last forever. I do not criticize those who open the old wax paper caps and hide new ones inside the old, or those who restuff can electrolytics, although I don't do anything like that myself.
Posts: 4,639
Threads: 51
Joined: Sep 2008
City: Sandwick, BC, CA
Texasrocker Wrote:I always "extricate" the old Philco orig bakelite blocks when electronically restoring vintage Philco & AK "coded" orig chassis components. I replace them with terminal-strips to mount new caps ( fully visable for the next tech to deal with yrs later), and therefore never have these grounding type probs. Keeping "authencity" hidden under these chassis is for the purists generally speaking? Does it really add any "value" to these sets? Does it ad probs re-building & re-installing orig bakelite cap blocks sometimes? Very glad you found the prob in your recap- restoration, and corrected it! Seems we have all learned something here all over again? ![Icon_wink Icon_wink](https://philcoradio.com/phorum/images/smilies/icon_wink.gif)
That will work well if you have a source of terminal strips but in some circles they are getting hard to find. In practice I don't find rebuilding the bakelite blocks any more difficult then replacing parts on a typical terminal strip when you get used to melting the tar out. Nobody would advocate replacing terminal strips and tie points in any other radio, the bakelite blocks are just Philco's version of the same. Speaking of which I am not normally into restuffing condensers, at least the tubular paper types, but with the bakelite blocks, or the tar filled cans used in early AC sets, it's a different kettle of fish due to the mechanical aspect and the lack of chassis space.
Best Reagards
Arran
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
I think most of us restuff the bakelite blocks.
In my misspent youth, I remember removing all of the bakelite blocks from a few Philco sets, and replacing them with terminal strips. Then I learned how to do things the right way.
--
Ron Ramirez
Ferdinand IN
Posts: 201
Threads: 26
Joined: Dec 2005
City: Morris Plains, NJ
I totally agree with those who restuff blocks. With practice it takes three minutes to gut, clean, and restuff a block; resoldering is quick since the wiring and components don't need to be moved or stretched. It also makes future service much easier for techs who use the original diagrams- like me. When I see a Philco that has had a block-ectomy, I stay clear.
Pete AI2V
Posts: 909
Threads: 117
Joined: Jun 2007
Now Guys!...,( hee hee) now Pete, a Philco "blockectomy" sounds VERY serious!!! I totally understand why it is easier in some cases to use the existing bakelight blocks, and keeping originality in some cases. For me, it is in reverse, since many of the old Philco bakelite condensers solder- points were used as tie-points anyways, I prefer the terminal strips. I call that a "terminal-blockectomy condition"!!!!,( hee hee),... and some of the more "cancerous-conditions "of orig Philco bakelite types had new caps "tacked-on" only, with orig caps left hidden- underneath still in-circuit also, which I call a " triple-bi-polar,cancerous, blockectomy" ready to happen again in the future with orig- parts hidden underneath!? If the old techs tried just "tacking new parts in place" on existing vintage Philco bakelite condensers,just like we all have seen new filter-caps tacked onto orig points of B+ origins, reckon anyone in the future may think it is also a good idea to "tack on" to your recently rebuilt Philco bakelite blocks without fully removing the old parts underneath first?
Im jus KIDDIN Ya'LL !! ... but I never heard of a Philco "blockectomy" before!! Thats Good!!When I replace the bakelite blocks, I do a very nice presentation of installing the terminal-strips, and work is neat & tidy also! I have "no-quarrels" at all with my Philco Pfriends that rebuild bakelite blocks at all! I understand the originality concept very well, and its kinda like using "bondo" on car repairs to some using term-strips I knowq, but replacing bakelite blocks w/ terminal-strips ( and well marked components easily seen & identified) can keep the "guesswork" out my restorations for future vintage radio techs to 'preciate also?, without the hassel of ever removing them bakelights again!To some future techs, my idea may be called "terminal genious"!?? Reckon?? ( hee hee, only guys!!) Thanks for putting up with me!The vintage Philcos chassis' are definately "terminal-friendly" indeed!
Posts: 31
Threads: 4
Joined: Aug 2007
OK, well I'm about ready to "Terminate" this thread. You always take a risk when you start a topic by admitting how you made a mistake, which opens you up for a friendly jab from someone with a better way. Glad to see the concensus position is "in the blocks", and there are some preservationists out there. I think the only point here was to let others know that wire pinching can happen, and that it's something to think about, especially if you are 57 years old and your eyes are getting less sharp than they once were. Fortunately with some experience we find our mistakes more quickly than in the past.
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
bridkarl
|
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM |
Cannot Adjust an IF Transformer’s cores
|
Joseph, now you are an engineer!!RodB — 06:37 PM |
PT-6 antenna connections
|
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desi...RodB — 06:34 PM |
Cannot Adjust an IF Transformer’s cores
|
It works! I received the PCBs this morning in the mail, and put everything together. I reused the base from the original...jrblasde — 04:32 PM |
PT-6 antenna connections
|
I seem to have lost my way on this PT-6.
I see the antenna aerial transformer schematic - I’m reading pins 1 through ...bridkarl — 12:30 PM |
40-150 General questions
|
Good thing you're a good electrician ... the pictures show a lot of rewiring in your future! Take care and BE HEALTHY!...GarySP — 11:52 AM |
40-150 General questions
|
I think RobB has it right. It is a part number and looks like its stamped on the chassis and that wasn't something you ...klondike98 — 11:41 AM |
40-150 General questions
|
It's most likely a part number. Most of Philco part numbers are in that format. I looked at the parts list for this mode...RodB — 08:10 AM |
40-150 General questions
|
Hi Kevin,
No, I don't but I like your Quote about being a good electrician. The way I look at it is "The fact ...MrFixr55 — 08:06 AM |
Philco 38-7 Speaker
|
7K should be fine. While not a perfect match (This transformer is meant for 6V6 tubes), Antique Electronic Supply (AES)...MrFixr55 — 08:03 AM |
Who's Online
|
There are currently 3047 online users. [Complete List] » 2 Member(s) | 3045 Guest(s)
|
|
|
![>](https://philcoradio.com/phorum/images/bootbb/asb/right_arrow.png)
|