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Author Topic: RESTORED SBE MODEL 33 HF RIG  (Read 2784 times)
W4OP
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« on: May 04, 2013, 02:16:22 PM »

I just posted  photos of the restored SBE 33. Pretty rough when it arrived, and of course, not working. When I checked the oscillators (VFO, HFO, Carrier) I quickly found the HF oscillator was dead. Fortunately- all of the active devices are socketed. Unfortunately, getting at Q3 meant removing shields and tilting the front panel out. E/B/C voltages were all off. Upon inspection, Q3 was a silicon NPN and should have been a Ge PNP. A couple of walks through alignment and a new 12BY7A (subbed  for a 12DQ7) and the radio was working. BTW, I had 3 new 12BY7A's and one used. The used one generated 3dB more Po than the new ones.

I changed out the mic gain pot for one with a switch so I could disable filaments when just listening. I also added a Cumbria Designs X-Lock to the VFO (although it was already much better than the SBE  34 VFO's) and an external counter designed to look like the SBE gear. Anyway, the rig is very creatively designed  both mechanically and electrically. Faust was way ahead on this one. If you have a chance to acquire  a 33 (I prefer it over the 34) pick one up. Where else will you find a rig with a stainless panel and all robins egg blue knobs and escutcheons?

http://www.parelectronics.com/vintage-sbe-33.php

Dale W4OP
« Last Edit: May 04, 2013, 03:03:30 PM by W4OP » Logged
KB4QAA
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« Reply #1 on: May 04, 2013, 03:32:34 PM »

Very nice job Dale!   The counter looks fabulous.  Seems the  Cumbria Designs huff n puff stabilizers are becoming popular.

Thanks for sharing your work. The website is super.  Bill
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W7VO
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« Reply #2 on: May 04, 2013, 03:59:17 PM »

I used to work for the SBE factory on Airport Blvd in Watsonville, CA in the mid 70's repairing the customer returned ham gear. The SB-33 was the easiest to work on, the SB-34 was right behind it, and the SB-36 (actually a re-branded Robyn product from Japan) was a real POS. (But did had an "ahead of its time" nixie tube display....).

The biggest problem with SB-33/34 were people that "fixed them" before they sent them in for repair. The combo VFO capacitor/bandswitch was another problem child. Once we ran out of new stock of  the radios went back "beyond economical repair".

Most of the time with the SB-33 it was just replacing one of the germanium transistors and an alignment to get it rolling again.

The "dual use" circuits (same circuit used on Tx and Rx) of the SB-33/34 were very innovative!

Great job, and brings back many memories of my youth!

73;

Mike, W7VO
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AC5UP
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« Reply #3 on: May 04, 2013, 04:38:19 PM »

The used one generated 3dB more Po than the new ones.

It wasn't too unusual for a new tube to gain some transconductance efficiency after a few hundred hours of burn-in........... IIRC this had to do with the getter needing a little time and temperature to react with residual air in the envelope or possibly the cathode burning off impurities. Either way, new tubes can get slightly better after they've played for a while.
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W4OP
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« Reply #4 on: May 04, 2013, 07:22:47 PM »

Hi Mike et al,

I had an SBE 35 here for a short while (there are several pix on my site). It may have been a prototype. After many hours of work, I never got it fully playing. Some have guessed it was made in JA, but all of the parts I recall were American- including the crystal filter. Never owned the 36, although I have seen some for sale at hamfests. My CX-7A, due in this week also has Nixie tubes. Except for an early Heathkit counter, I think this will be my second Nixie piece.

The SBE counter now has a nice matching blue backlight- easier to read than the green also.

Dale W4OP
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K1ZJH
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« Reply #5 on: May 06, 2013, 10:23:11 AM »

Hi Dale, sure glad you posted this... I have two SBE-33 transceivers that need restoration. Now I am anxious to get at least one of them back on the air. Unfortunately, someone removed all of the tubes and transistors from one of them.

Pete k1zjh
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W4OP
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« Reply #6 on: May 06, 2013, 05:33:11 PM »

Hi Pete,
Hopefully you can  make one working rig from the pair. One has to wonder why anyone would strip the rig of the active devices though.
It really is a fun rig. Maybe a tad low on mic gain- I am using a preamplified handheld D-104 on mine.  Likely, the original mic was just fine.
Let me know if I can help.

Dale W4OP
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