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

650 alignment
#1

I am aligning a 650 and have the osc tracking nicely (adjust the trimmer in the can at 1600 and the outboard trimmer under the chassis for 610)

The RF does not track well in my observation. I can peak it at the high end or the low end and seems to be very sensitive. I could "optimize" it ,but it would be a shame to waste the gain for poor but even performance accros the band.

Am I expecting too much or should I look further.

Current conditions:
Total Re-cap
Out of tollerence resistors replaced
Tubes "tested" good
Using a 10' antenna for testing.
Blocks rebuilt

Looking for a clue,

Dave Casazza
Keep em glowin and goin...
#2

Mine act the same way, Philco or not. Connect up a 40' long wire, and it's hard to notice or gone all together. This is due to a more favorable L/C ratio in the tuning circuits on higher freqs. If everything aligned up as it should, try a longer antenna. I really doubt you have an issue.

-Brian
If you collect or are interested in antique telephones, please visit Classic Rotary Phones
http://www.classicrotaryphones.com/forum/index.php
#3

I just finished a 650B and found that the rf tracking can be improved on the broadcast band by cheating the dial scale alignment somewhat. With the tuning gang plates fully meshed, try setting the dial scale to the first line to the right of the end of scale line. Now re-align and check your rf tracking. If it is better, but not perfect, move the dial scale a little more in the same direction and try again. I found this procedure helps somewhat.

Ed




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
philco predicta
The model is the holiday without UHF It has no sound and I don't have an oscilloscope or signal generator.cgl18 — 08:51 PM
Philco model 38 code 121 not receiving signal.
I will definitely check my lead length and wire dressing. Thanks for the ideas.Stormlord5500 — 08:06 PM
Philco model 38 code 121 not receiving signal.
Do make sure that you twist the 3 wires from the chassis to the transformer, and dress away from tubes, especially audio...MrFixr55 — 07:38 PM
Philco model 38 code 121 not receiving signal.
The cone unfortunately got damaged when I removed it. The glue that held the cone to the basket was sloppily applied and...Stormlord5500 — 07:12 PM
Philco model 38 code 121 not receiving signal.
So what was wrong with the original speaker? Was the cone damaged? Unless it's totally hopeless I would put it aside as ...Arran — 05:31 PM
My collection presentation
There is an article on my site that introduces the first portable radios in my collection. I have only provided a link t...Vlad95 — 01:17 PM
Electrolytic restuffing/internals
Bridkarl This specific cap you have is the easiset type to restuff. I usually cut it at the upper border of the depr...morzh — 11:35 AM
philco predicta
Hi CGL18, First off, welcome to the Philco Phorum. I have not worked on a TV for a while but here are some givens: ...MrFixr55 — 08:22 AM
Another amp build - here I go again!
Sweet! I actually have a Dynaco Mark 4 that I had been running with 6L6s with no mods. Seemed to my 14-year-old head a...MrFixr55 — 12:57 AM
PT-6 finished!!
Hi Gang, Tube heaters are not "Ohmic" devices (that maintain specified resistance over wide temperature, c...MrFixr55 — 12:03 AM

[-]
Who's Online
There are currently no members online.

>