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

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Hallicrafters SX-62 - low volume
#16

This is coming along. Found a misplaced wire and a capacitor. Still need to go through and finish cleaning this up, but I think it’s much better. A new side cutting pair of snips has helped. I’ve put in two Sprague electrolytic caps. Very nice solid units if expensive. 
Just waiting for my NOS 5U4GB tubes to arrive. 
I think it will be ready this weekend to bring up with just the rectifier tube and see how it goes. It is unclear to me how much current it should be pulling with just a rectifier in place.


Attached Files Image(s)
               
#17

Quote:I think it will be ready this weekend to bring up with just the rectifier tube and see how it goes.
The B+ can soar without a load, possibly taking out the filter caps...

Set OFF, measure the DC resistance of B+ to B- at the power supply. That resistance will dictate the load current based on the highest published voltage in the schematic, usually at the screen of the output tube, if no rating the plate voltage figure would apply also. If the calculation exceeds 80ma recheck measurements and calcs. If consistent, check all B+ paths for miss-connections or shorts...

A resistance of from 15k and higher is good...

Any resistor/inductor in the main B+ line or B- can be used as a shunt to determine real-time current. Measure the devices resistance and record. Place a voltmeter across that device and power the set. the voltage measured calculates to the milliamps flowing in the B circuit...

Caution meter leads are live, avoid handling the meter...

The greatest consumption of B current is the output tube(s). Controlled by the grid voltage.

It is possible to alter the grid bias voltage as long as distortion is not introduced, doing so can save both tubes, output transformer and overall B current as well as a cooler operating receiver.

GL

Chas

Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
The thrill is gone again, thought I was close to being done with it. Well Friday it was receiving broadcast, Saturday mo...osanders0311 — 07:47 PM
Help with Supreme 599
Iam getting closer to fixing it. I bumped Up the tranny voltage to get 5v on the 80 tube. I gan get the needle to move ...daveone23 — 03:41 PM
Philco 42-345 Restoration/Repair
Hello RodB, Checking my previous post I realized you're the one with the 42-340. I replaced the string for the tuning...osanders0311 — 03:12 PM
5U4 vs 5Z4 tubes
I saw no evidence of anything going wrong. The transformer is fused already which is nice. Interestingly the 5z4 did...bridkarl — 02:37 PM
5U4 vs 5Z4 tubes
I doubt anything cooked in 30 seconds because of the oops! These are very similar tubes, and nothing but transformer re...GarySP — 02:30 PM
Restoration of the Canadian General Electric A-87
Paul Philco322.You will be keeping very busy, you may have to go back to work for a breakIcon_smile. Paul To rel...RadioSvit — 01:57 PM
5U4 vs 5Z4 tubes
I grabbed the wrong tube and put in a 5U4 tube instead of the 5Z4 - I just had the rectifier in with no other tubes. Af...bridkarl — 01:54 PM
Restoration of the Canadian General Electric A-87
After applying the filler to the entire body, I noticed that the shades of the facade and the side and top walls were ve...RadioSvit — 01:49 PM
Restoration of the Canadian General Electric A-87
You will be keeping very busy, you may have to go back to work for a break:). PaulPaul Philco322 — 01:46 PM
Restoration of the Canadian General Electric A-87
After removing the control knobs, chassis, dynamics and scale frame, I first started restoring the torn piece of veneer....RadioSvit — 01:20 PM

[-]
Who's Online
There are currently 1036 online users. [Complete List]
» 2 Member(s) | 1034 Guest(s)
AvatarAvatar

>