Thanks, Brett
The R-54 (R-74) schematic was also published in the Canadian RCC manuals. It's on this site and you can find it on the link below. It might be a little clearer than both those two RCA scans.
That link
http://www.nostalgiaair.org/PagesByModel/064/M0030064.pdf
Best Regards
Ken
Thanks, Brett
Brett
I can certainly see the difficulty in reading out the value of the 500,000 ohm tone pot, but the C30 tone cap can be read
out as as .02 ufd.
73's de Edd
Riders Volume 3 - RCA 3-34
Thanks, Brett
I can certainly see the difficulty in reading out the value of the 500,000 ohm tone pot, but the C30 tone cap can be read
out as as .02 ufd.
O.K. then, there is additionally the fixed, in circuit capacitor C29 that is initially holding back the very highest treble frequencies.
Its value is 745 mmf-----pf's.
Now, in these times, one would use a common dipped silver mica capacitor of a 750 pf rating for its replacement. The same type for the other ones you found also, with you not mentioning their locations, but I am familiar with that ooold style of crimped metal casing construction.
73's de Edd
Brett:
I might get some disagreement on this, but in my opinion (humble or not) there is such a wide tolerance on these electrolytic caps, and so much "slop" in building them, that most anything remotely close to the original capacity should work. At least, you are not going to hurt anything, and you can always put something proper in its place if you are not happy with the results of an experement.
Lewis
A lot of electrolytics are rated +20/-80% too, so your thoughts are on target.
marv
::Good, I read it at 745mmfd also but wasn't sure (should these be replaced?). Question 2. In the cap can of 13 caps there are (3) 10uf caps and (1)7uf. I can't locate a 6.8uf and another 10uf would be out of the 20% spec. Also, what type of cap should I use for this Application. There's a big price difference between caps.
:
:
:Brett:
:I might get some disagreement on this, but in my opinion (humble or not) there is such a wide tolerance on these electrolytic caps, and so much "slop" in building them, that most anything remotely close to the original capacity should work. At least, you are not going to hurt anything, and you can always put something proper in its place if you are not happy with the results of an experement.
:Lewis
:
Methinks that the server possibly corrupted the figures or your having an errant synapse enacted a dyslexic typing transversal of +/-‘us-es-es.. . . .lol.
A lot of electrolytics are rated +20/-80% too, so your thoughts are on target.
A lot of electrolytics are rated -20/+ 80% too, so your thoughts are on target ..
(I've even seen +100 thru +200% specs. . . .ergo. . . . seems like rolling capacitors and computing electrolyte action is STILL not an exacting science.)
73's de Edd
:Lewis,
:A lot of electrolytics are rated +20/-80% too, so your thoughts are on target.
:
:marv
:
:::Good, I read it at 745mmfd also but wasn't sure (should these be replaced?). Question 2. In the cap can of 13 caps there are (3) 10uf caps and (1)7uf. I can't locate a 6.8uf and another 10uf would be out of the 20% spec. Also, what type of cap should I use for this Application. There's a big price difference between caps.
::
::
::Brett:
::I might get some disagreement on this, but in my opinion (humble or not) there is such a wide tolerance on these electrolytic caps, and so much "slop" in building them, that most anything remotely close to the original capacity should work. At least, you are not going to hurt anything, and you can always put something proper in its place if you are not happy with the results of an experement.
::Lewis
::
So what is the prognosis for my severe case of dyslexia (I think) at 70 yrs? Am I hopeless, or is there a cure for my errors of transposition. Can I be rehabilitated and remain a contributing member of the NA Forum? Reminds me of a joke of yesteryear concerning a period (.) I stand corrected, but remember seeing that particular tolerance quote on several old can style capacitors.
marv
marv
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:Methinks that the server possibly corrupted the figures or your having an errant synapse enacted a dyslexic typing transversal of +/-‘us-es-es.. . . .lol.
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: A lot of electrolytics are rated +20/-80% too, so your thoughts are on target.
:
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:A lot of electrolytics are rated -20/+ 80% too, so your thoughts are on target ..
:(I've even seen +100 thru +200% specs. . . .ergo. . . . seems like rolling capacitors and computing electrolyte action is STILL not an exacting science.)
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:73's de Edd
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::Lewis,
::A lot of electrolytics are rated +20/-80% too, so your thoughts are on target.
::
::marv
::
::::Good, I read it at 745mmfd also but wasn't sure (should these be replaced?). Question 2. In the cap can of 13 caps there are (3) 10uf caps and (1)7uf. I can't locate a 6.8uf and another 10uf would be out of the 20% spec. Also, what type of cap should I use for this Application. There's a big price difference between caps.
:::
:::
:::Brett:
:::I might get some disagreement on this, but in my opinion (humble or not) there is such a wide tolerance on these electrolytic caps, and so much "slop" in building them, that most anything remotely close to the original capacity should work. At least, you are not going to hurt anything, and you can always put something proper in its place if you are not happy with the results of an experement.
:::Lewis
:::