Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

Sencore SG165 rf problem
#1

I have a sencore sg165 analyzer that came with some of the usual problems I have read about online. The am/fm tuning cap shaft was broke. I repaired it and have accurate am freq. readings but no fm readings.
I checked the tr314 tr 315 out of circuit and they test good.
Any help with what to check next is appreciated. Also all the other settings sine, square wave and sweep etc. appear to be working correctly. Thanks for help.
#2

Have you looked with a scope? It is fairly small output.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#3

Thanks Mike, I did have it hooked to scope when checking the sine/ square wave ,not the fm frequency. With the tuning shaft broke after fixing , I was using an B&k 1gig frequency counter to test the fm frequency. The am is reading fine. I will have to reinstall the main rf board and transistors to get it back to look at on scope. I would think the fm should read on the frequency counter. The counter reads all the fm frequencies on my leader lsg 215a signal generator.
Before removing the main RF board I did check the volts from ground to base of the tr315. It read -12volts. according to manual oscillator tr314 runs only when there is 12v+ at base of tr315 turning it on and supplying emitter current to tr314. I don't know why it had 12v- at base. Thats why I thought I had a bad tr315 transistor. The molex plug to RF board from the power supply board have both -12v and 12v+. I will try to get the schematic downloaded and put up here.

http://s1336.photobucket.com/user/220koh...c.jpg.html
http://s1336.photobucket.com/user/220koh...b.jpg.html
Here is the rf section of the manual.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
That looks a lot like an aircraft connector of some kind, even if it's a U.S.N power supply. I have a book somewhere abo...Arran — 02:56 AM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
hello david, I have a similar generator in my collection that features a cast iron, single-cylinder Briggs & Stratt...radiorich — 01:00 AM
under chassis parts locator diagram for 1938 Zenith 9s262
Has anyone gone to the trouble of creating an under chassis parts locator image?  Yes, I can identify components by foll...bobloney — 08:57 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Try looking at this site the book mark is for a old generator that I was given. David    https://radionerds.com/index.ph...David — 08:36 PM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
Hello Everyone, I am looking for voltage identification for all the pin positions on the socket of a CRV-20130 power su...Tonym4704 — 08:16 PM
Philco P45-6365 Universal Transformer Instruction Manual
Can anyone guide me to where this may be found?GRG — 03:00 PM
54C Complete Teardown/Rebuild
I don't think that I have encountered a 12Z3 before, curious how it uses one of those but includes a #43, which is a 25 ...Arran — 02:17 PM
HiFi (Chifi) tube amp build - but my own design.
It's the other forum. I'm also in DIY, but mostly read there. Honestly, I kinda jumped into this without much thought to...TV MAN — 10:43 AM
Philco 71 Code 125
Hello,  I am in need of a schematic for this radio. Mine has the three separate circular tube shields and a shadow me...dconant — 08:06 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated.dconant — 07:57 AM

[-]
Who's Online
There are currently 1679 online users. [Complete List]
» 1 Member(s) | 1678 Guest(s)
Avatar

>