EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Happy to have found this site. I have a WWII Low radiation SLRF Receiver in pretty good condition.

I've had it in my "to do someday" pile for about 35 years. I've gotten my other boat anchors up

and singing again. I have the SLRF manual. Anyone familiar with this radio that can offer me

some advice? I have found very little on the web about it. Thanks in advance.

Jim KM4HI

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Just came across your post.  Surprised you have not received a response yet.  I have the Navy version of this receiver, the RCH.  The only trouble I have had with it is the shorting of a couple of the IF stage screen bypass "bathtub" caps, which when they short out, will fry the associated 1K ohm screen dropping resistors.  I have successfully replaced them with Radio Shack resistors.  I think I went up one wattage rating from what is specified in the manual.  At least one of the resistors was still working after being fried, but promptly fell apart when I touched it with a plastic alignment tool while chasing down intermittent noisy operation after I had replace the associated  bypass cap.

I have read somewhere that the large filter caps in this and other WW2 military Scott sets are oil filled rather being electrolytic paste types, and will likely not be an issue when powering up a set that has been sitting unused for many years.  That was certainly the case with my RBO, the only electrical problem with it when I powered it up after probably a couple of decades was an open first detector to first audio coupling cap. Just be sure to check the B plus circuit for any low resistances to ground before powering up  the set for the first time.  It will be more likely that any low resistance will be due to the bathtub bypass caps.  When I cleared the shorts on those in my RCH, I believe that the B plus line to ground read as a virtually open circuit.  If you are seeing something like 1K ohms to ground on the B plus line you are likely looking at a shorted bypass cap through its associated dropping resistor between the cap and the main B plus line.  You should also check the individual B plus bypass caps at their terminals in case they have taken out the  associated dropping resistor, check the resistors also for proper resistance and for any visual indications of over-heating.

James -

If you click on the "Scott Info Archive" link above and go to "Set Folders" and then "WWII Sets", you should be able to locate a PDF manual for the SLRF. If you don't find it, let me know. 

Kent

Thank you very much, Kent, for your most valuable input. Good to know the filter caps shouldn't need replacing. I like your approach to measuring the B+ circuit resistance before applying power. I also use a variac to ramp up the power when the time comes for the first "smoke test". In the schematic I see two 6SK7's in the IF strip. V104 with C112 & R120 in the screen circuit. Likewise V105 with C108 & R121. I have the correct ones? The caps are .05@600vdc.  Any issues with the bathtubs below T-116 & T-117? I will check the entire  B+ line as you recommend.  Also will look for the PDF if I need it. My manual is not in bad shape but need a magnifying glass to read the schematic part ID numbers.  They don't make manuals like this anymore.  The set was last powered up in the early 70's, I think it was receiving ok. Thanks, again, Kent.

Regards - Jim KM4HI

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