Antique radios, Old Time Radios

SABA 446 WLK - Repair Help

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Roee Sulimarski IL Articles: 3 Schem.: 0 Pict.: 0 08.Aug.08 16:06	SABA 446 WLK - Repair Help You aren't logged in. (Guest) 1 Hi, I am a new member at "Radio Museum" , and I need help repairing my new old Radio - SABA 446 WLK. I downloaded the schematics from the web and checked the radio . the problem I have is that I am not able to receive any AM (Middle range) station which transmits at my area. from the examination I did to the radio, it seems like the amplifier circuit which services the TT input works well, but the receiver first stage doesn't respond at all. when I checked the voltages on one of the grids of the AK2 tube I was measuring -12Volts (does it make any sense? where can such voltage come from?). I would appreciate any help someone could give!!! Thanks in advance, Roee. I attached the relevant schematics. Attachments: Saba 446 WLK scematics (149 kb)
Martin Renz D Articles: 334 Schem.: 97 Pict.: 118 12.Aug.08 08:12	You aren't logged in. (Guest) 2 Hello Roee, your question was about the -12 V at the Grid of AK2. Measure the Voltage at the 250 ohm resistance. You will find it there, caused of a current of 5mA. That is not the problem of your receiver. In case your oscillator is running, it might be detuned. Its frequency will be far away from the 468/492 kHz .This can be caused by bad capacitors. Saba used silver micas during these years, that often are destroyed by corrosion of the silver plate. They look like this one: You will find them here (the 220p ones): If their capacity is to low or zero, you must change them with new silver micas of low tolerance. There might be more problems, like bad coil cores, which are difficult to repair. Resistors like these are sometimes broken, you should check them. Without equipment like a AM signal generator it will be difficult to repair this radio. You should check every part of the circuitry from the back. Please note that I am no expert in this kind of repair. I repaired a Saba 452WK with success and I describe here my experience with this model. Any other experts are welcome to help. Martin Renz
Roee Sulimarski IL Articles: 3 Schem.: 0 Pict.: 0 14.Oct.08 20:33	SABA 446 WLK PHONO INPUT PROBLEM You aren't logged in. (Guest) 3 First of all THANK YOU VERY MUCH Martin!!!! you helped me alot - thanks to your detailed answer I managed to fix the Radio Receiver. Second - in the WLK 446 there is a mono phono input at the back of the radio. I tried to connect one channel (L\R) of my Dual 1249 Turn-Table in order to listen to a vinyl record, but the volume level at the speaker was very poor (almost hear nothing), although the volume control switch was at the highest level... does someone can help me to solve it? P.S. when I hear A.M. Radio the volume at the speaker output is high enough.
Hans M. Knoll D Articles: 1257 Schem.: 137 Pict.: 59 14.Oct.08 21:31	You aren't logged in. (Guest) 4 Hello Roee. You need for this Radio, a RIAA- Equalizer- Preamplifier like this or this She must have a gain from 34 to 40 db ( 50x to 100x amplification ) Or, a high level cartridge "ceramic" like DUAL CDS 650 (Keramiksystem CDS650) Regards Hans This article was edited 15.Oct.08 11:00 by Hans M. Knoll .
Roee Sulimarski IL Articles: 3 Schem.: 0 Pict.: 0 18.Oct.08 20:05	You aren't logged in. (Guest) 5 Thank you very much Hans , I see that the one you recommanded on is an inside installation especially for dual, http://dual.pytalhost.eu/tvv47/TVV47_08.jpg thanks agagin, Best Regards, Roee.

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