[n9vu]

OK, making progress in rebuilding old bakelite blocks however there's a stumbling block, so to speek. The 6287F's require replacement of 2 ea .15 mfd caps. What's safe to sub for this? I can only think of going down with a readily available round of .1's. Will this be tolerant within the twenty percent rule? I always thought you had to meet or EXCEED the value, but that may be for the largers.

Your help would greatly be appreciated. Philco's ROCK when recapped.


GB

[planigan]

Gary, what circuit are they located in? The values may not be that critical depending on the use there put to. Are these line caps? Pat

[n9vu]

Gary, what circuit are they located in? The values may not be that critical depending on the use there put to. Are these line caps? Pat

Pat,

Shows you what I know. The block is under the rear of the set under the two up right 8mfd caps, but not under the main power transformer. I would assume this is a power supply circuit, but may be wrong.

[rghines1]

What's the model and item designation from the parts list (Cxx)?

[planigan]

Model # and part # would be very helpful but location may indicate line caps. On that block does the line cord come in to the chassis and run to that block? Both sides of line cord? If so they are probably line caps and should be replace with the new "safety caps" which when they fail, fail open, no short. The high mfd is kind of high even for line caps which usually are around .015mfd. These may be additional filtering caps? Best get the schematic before deciding what to do. Pat

[n9vu]

Model # and part # would be very helpful but location may indicate line caps. On that block does the line cord come in to the chassis and run to that block? Both sides of line cord? If so they are probably line caps and should be replace with the new "safety caps" which when they fail, fail open, no short. The high mfd is kind of high even for line caps which usually are around .015mfd. These may be additional filtering caps? Best get the schematic before deciding what to do. Pat

This is the Philco Model 16, Code 122. The block is way on the opposite side of the line and is not wired to this individual bakelite block if that's any indication. Appreciate your help.

[rghines1]

This should be C86 from the Nostalgiaair schematic:
http://www.nostalgiaair.org/Resources/139/M0013139.htm

This is an interesting thing Philco did. The two 0.15 caps are together to make 0.3 uF in parallel with the filter choke. This is a resonant circuit at 120 Hz (twice the line frequency) to further help reduce hum. You will want to stay close to 0.3 uf. The voltage across these caps is less than a hundred volts.

See if you can get three 0.10uf/400V poly caps in parallel inside the bakelite block to make up a 0.3 uf cap. Using 630V caps may be too big to get three inside the block.

Richard

[n9vu]

Richard,

Thanks for the info. Hmm. As far as I remember the 6287F that this thing is in has two 1.5mfd but not in parallel, more like separatly wired one on one terminal, then 2nd on another or maybe I'm wrong in my observation. Will give it another look. Appreciate your help and input.


GB

[Terry Judkins]

They are wired in parallel externally. I have put a single .33 uF 200V cap in the bakelite block. Works as designed.

[planigan]

Gary, correct me if I'm wrong but I have been under the belief that we are dealing with a Philco 16. Based on that assumption the block is part number 6287 J (I believe you label it F). Part number 6287 is a double .15uf block. Both caps are in the 1 AF circuit, one in the grid and one in the plate/grid 2d AF. They are not in parallel. Both share the common gnd terminal on the block but go to two different terminals.Some where in this string the value pops up as 1.5uf, at another they are in parallel and total(.15uf in that string part) .3uf. First, if my assumption is right (Mod 16) they are .15uf caps and not in series or parallel. What was being pointed out is that if you can not find a .15uf cap (http://www.justradios.com has .15uf, 630v, metalized poly) you could put two .07uf caps in parallel with each other and get a .14uf cap (in his example three .10uf to get a .3uf). You would not then put those two in parallel with another set because thats not what the block calls for. You would connect each of the two cap assemblies to the gnd term and the the other side of each assemble to there respective terminals (I didn't look up the schematic for the 6387 so I don't know the term #s) such as term 2 and term 5. I ran into this problem on a 37-650, it has two 110pf 1300V in one block, both to gnd and then one to term #2 and the other to term #3. I used two 220pf 500V in series (110pf, 1000V[sorry no 1300V]) as substitutes for each of the 110pfs. I ended up with four caps in that block. I hope this straightens this out because it was becoming very confused. I also hope I didn't add to the confusion. Just as a rule of thumb with two caps of equal uf, when you put the caps in parallel you add the uf, voltage remains the same: when you put them in series you halve the uf and double the voltage. Pat

[n9vu]

Pat,

Thanks for the information. You have the right chassis and bakelite block description, but this looks like a difficult match, at least with what I have available to recap with. I may have to rely on an outside source after all for recapping this block. I doubt if I even have two .07's to place in parallel.

I'm wondering if it would cause much harm or hurt the performance of the set to run .1's on each side, or UP the odds with two .1's to make .2 on each side. My only concern is that you or someone else in this string mentioned something about this being a critical resonant circuit, but how critical is it to vary the difference in caps?

I do appreciate your help, input, and information. You haven't caused any confusion at all. At least now we're on the same track.


Thanks,

GB

[planigan]

Gary, you could use three .05s but you most likely would have to use a shoe horn to get them in the block. My last suggestion, e-mail me at planigan@suffolk.lib.ny.us with your postal address and I'll send you two .15's that I have and can't remember why I got them. One is an X2 safety cap ther other is ceramic. On the 37-650 I'm restoring two safety caps fit in the block so you should have no problem. Pat

[planigan]

Gary, I forgot to add that if you use three .05uf's you would have a total of six caps going into that block, ergo the shoehorn remark.
Pat

[n9vu]

Gary, I forgot to add that if you use three .05uf's you would have a total of six caps going into that block, ergo the shoehorn remark.
Pat

Oh yes, I figured that, LOL. A shoehorn does wonders. If this is the route I take, it may even fit the bill a bit better to mount them outside of the bakelite block, but wouldn't that look awful?

I appreciate your help, and thanks,

GB

[planigan]

Gary, do you want those caps? Pat