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Author Topic: Antique Radio Restoration Help Needed! Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 12-09-2005 12:41 AM                     Hi Phil and Mark My parents were married in '67. The set looks something like the bottom row second from the left. The top dial was for standard broadcast stations and the bottom dial actually had two knobs: one for UHF stations if I remember, and the outer part was for picture adjustment. The cabinet "boarder" below the screen was actually a door that opened where all kinds of picture adjustment (color adjustment knobs) and the like were. The picture tube had finally worn out and was too expensive to replace. So to the trash it went. But that cabinet was quality wood. I wonder what that set is worth today? The 816K article link you posted is the actual article that got me hooked on this radio. I was a subscriber to ARC back then, and still have the original issue. I kept it vowing that I would one day have that set...but it was one of those back-burner type projects that took me 15 years to get around to. Chuck Dachis influenced many people with this article. Restored, market value is around $1000.00 - $1200.00, but you can occasionally find them dirt cheap at ye ole junk-garage sale. They have an excellent sound and that electronic tuning works beautifully. If you can find it, there was also a arm-chair remot controll accessory. It also has phonograph and external antennea hook ups. Cheers K  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 01-17-2006 06:39 PM                     I came up with wire for my RCA 816K restoration, and this source might be useful for some of you. Pacer Electronics in Tempe, AZ (480) 544-9000. Ask for Bob Their usual minimum order is 100 ft lengths, but they were kind enough to do 25 ft lengths for me. All wire that I purchased was 18 AWG UL 1015 (600V/105 degrees C) rated insulation, and the UL specs are printed on the wire. Wire is tin coated copper stranded. Solid colors were about $3.00/25 ft or about $0.10/ft They also do custome color code striping on site. So, a 25ft roll w/custom striping was $8.00. I now have all the correct wire to complete my restoration. Cheers K [ 01-18-2006, 03:11 PM: Message edited by: Will Kutler ]  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 01-17-2006 07:35 PM                     quote: Will Kutler I wonder what that set is worth today? Nothing or less than nothing. In reality it should be a freebee if you ever run across one. The only B&W TV's that have any real worth are most of those made before 1948, The Zenith Porthole B&W sets of the late 40's to early 50's, or some of the 1960's Philco sets. Pre WW-2 B&W sets generally go for 5K and up. The Marconi Phone TV at the link on the previous page is easily a 10K set in working condition. An RCA CT-100 color set is also around 5K in not working condition but with a good CRT.... which is extremely rare. Most of those CRT's have gone to gas. Thanks for the info on the wire, that may help me out in re-doing an RCS 621TS!! Mark  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 06-17-2006 01:16 PM                     A question for both Phil and Mark G. The RCA 816K that I am STILL working on has numerous mica caps, some of which are temperature-stabalizing. I would like to identify which of these caps are temp-stabalizing. I do have the original RCA 816K service manual and schematics. The parts listing just has the original RCA part # and the Mmfd value. Unfortuantely, I have not been able to cross-reference or find any info regarding the original RCA part numbers. Furthermore, the schematics do not specify the temp-stabalized caps, either. What is stated in the 816K service manual is that: "The antenna and first-detector coils are constructed with a special type of winding ("qumulative") to provide increased sensitivity on the "Standard Broadcast" band. Special capacitors shunting the spread-band oscillator coils change in capacity with temperature variations to reduce oscillator frequency drift." "Spread-band tuning is accomplished electrically by shunting the low-capacity section of the oscillator variable capacitor with relatively large temperature-stabalized fixed capacitors for tuning the oscillator coil on the "19M", "25M", "31M" and "49M" bands. Antenna and first-detector coils are designed to be sufficiently broad-tuned to require no variable tuning over the narrow frequency range of the spread-bands." "The 100 mmfd. molded Lucite capacitors which connect in parallel with the bandspread oscillator tuning condensor for short-wave operation are specially designed to have a negative thermal coefficient of capacity to compensate for variations in other parts of the oscillator circuit with temperature changes. These capacitors are therefore not inter-changeable with ordinary types and replacements should always be of the particular RCA stock number specified in the Replacement Parts List. Care must be exercised in replacing these parts, to avoid twisting the leads excessively and allowing too much heat to be applied when soldering." There is also mention that these caps are marked 1A, 2A and 3A. I found caps marked 1A and 3A, but not 2A. From what I have been told, it is usually not necessary to replace mica caps, as they generally do not go bad. However, I do wish to at least inspect them, as some may be suspect. How do you inspect the temp-stabalizing characteristics of these caps. Mark and Phil, if I sent you coppies of the service literature, could you identify these caps and possibly recommend a proper replacement should mine be bad? Regards Kutler  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 06-17-2006 05:59 PM                  Will, email me the stuff...I'll see if I can help. quote: Will Kutler From what I have been told, it is usually not necessary to replace mica caps, as they generally do not go bad. That's not necessarily true. While the mica itself doesn't change value, the encasement package material can become porous over the years and absorb moisture which then changes the reactance, and thus the in-circuit value of the cap. Also, back then they were called condensers, HA!  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 06-17-2006 06:24 PM                     Hi Phil Can you give me your snail-mail address. I don't know if I have access to a scanner...but I'll see. You hit the nail on the head. Many of the caps have bad encasing material...that is why I think they might be compromised. There are no dot-codes on my caps. Most are of two different sizes... black bakelite, retangular about 1 1/2 inch long, 1/2 inch wide and 1/2 inch thick with chamfered corners. The others are about 1/2 the size of these. They have numbers on them like "T#", "V#", "M#". The ones marked "1A" and "3A" are encased in a clear plastic material. From what I understand, both temp-compensating and temp-stabalizing mica caps do two different things. The manual only mentions tem-stabalizing, but I am wondering if both are used? Thanks Phil K  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 06-17-2006 06:40 PM                  Let me know if you can find a scanner, else I'll PM you my address. I've seen old mica caps that actually cracked open from the absorbed moisture and then froze because they were left out in a garage during Michigan winters. Temp-stabalizing is a function/method. Temp-compensating is a part type/characteristic.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-17-2006 07:20 PM                     Phil is rignt about the Micas! I'd replace them all with the newer silver mica caps... the dark red/purple jobs that alot of parts stores sell. Those are alot more stable and less failure prone over the years than the old micarts cased versions. I've actually had several of the old style caps fail in my antique RCA tv sets. One of them was right across the power switch... it failed on its own... I came home from work one night and the tv was on... and the on-off was off! Ever since that episode I replace them all, ya don't want to burn the house down. I'm not the sort of person that perfers to have the set's chassis look EXACTLY as it did when it left the factory... I would much rather have it perfrom even better than it did when new of it can... I even so a sweep alignment with a modern synthesized sweep /RF generator and spectrum analyzer of the tuner and IF strips to get things as good as they can be. Old TV shop gear doesn't cut it compared to the results you get with new test gear. BTW: If you get 5% tolerance silver micas as per the values in the schematic... 5% is quite common... they will be very temperature stable without having to seek out special temp stable caps impractially made from umobtanium.... BTW#2: Ha! Unobtanium comes from about 960'down this unobtanium mine shaft..... the last date that RCA's unobtanium miners went down there couldn't be obtained. If there needs to be a new supply of unobtanium then you can go down there and get it yourself! I ain't a goin! I'd settle for those 5% silver micas from the local parts store... The silver to make those is very obtainable even today... locally here in fact Mark  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 06-17-2006 07:22 PM                     Hi Phil and Mark I found Riders on-line. It looks alsmost like an exact reprint of the original RCA 816K manual. http://www.nostalgiaair.org/Resources/155/M0015155.htm I am also with you on your restoation philosophy, Mark. I want a radio that I can reliabily enjoy on a daily basis. I would like to put her back together via the correct chassis layout using correctly colorcoded wire, etc. To me using components of proper values such as caps and resistors is the most important thing. To me using newer style more reliable components like these is most important. However I will keep and store the original components that I replace. Some restorers are into opening up origninal paper caps and stuffing them with new components, etc. to maintain original appearance. And there are a few companys out specializing in the reproduction of original style paper caps. Thanks K [ 06-17-2006, 08:33 PM: Message edited by: Will Kutler ]  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-17-2006 10:29 PM                     Yea, there are fanatical restorers out there thats for sure... to me getting the best performance out of an old piece AND not burning your house down are the two most important things. You can't tell from the outside that there might be Sprague Orange Drop caps on the inside! My RCA 639 was factory wired with all light brown wire... makes it kinda easy. I had to relace alot of it too... RCA is famous for dry rot. Mark  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 06-17-2006 10:47 PM                     Mark From everything I have read and been told about antique radio restoration: Micas rarely need replacing and good luck cross referencing the original RCA part numbers (finding their values and referencing them to new parts). But what concerns me is that the Bakelite and Lucite casings on my caps have seen better days, and I am concerned that the caps might be affected. So, is it possible to measure each individual mica cap and determine if it is temp-compensating or temp-stabalizing? Or can this be determined by an exerienced electronics designer by looking at the schematics and guesstimating? Are these type caps necessary, or will the 5% silver micas be a good generic substitute? Cheers Kutler  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-17-2006 11:25 PM                     In my expereince with antique TV's the 5% silver micas work very well and they are ALOT better than the original parts that were used. If you are unsure about the actual value of the cap or caps then using a capacitance decade box helps in getting the exact right value in place in a live circuit. Also subbing in slightly differnt values till the curcuit tunes or works correctly is another way. You can aso get a capacitance meter and measure the dang things at different temperatures to see whats going on with the originals... or the new replacements... the old ones may actually be just fine but in my opinion are still a hazard in an every day used antique piece of electronics. Mark  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 06-18-2006 07:04 PM                        I am totally in agreement with Mark on the primary side of the transformer. On the other side, I try to make some judgement based on reliability or possible failure mode.Sometimes "high voltage" (over 80 volts) is just not that reliable unsupervised. Louis  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 06-21-2006 10:09 PM                     Hi Phil I sent you a pm with the requested info several days ago. Do you recieve it? Thanks K  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 06-22-2006 02:42 AM                  haven't got it... Did you send it to my PM addr as listed in my ID bio? Do NOT use the FT mail system.  |  IP: Logged

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