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

Thread Closed

Philco Bristol update
#1

    So after a few months of waiting I finally had a chance to fire up the newly restored chassis for the first time yesterday. It's great to see beautiful vertical deflection without even having made any adjustments yet. The horizontal, well a couple problems. The first problem that I realized about 2:00 a.m. overnight is that I forgot to install the new horizontal AFC diodes! Second the flyback was doing its best impression of a tabletop candle with small wisps of acrid smoke gently wafting out of the high voltage housing. I don't think my issue for getting the diodes would have anything to do with that. This flyback was suspect when I pick the setup a long time ago and I have a replacement to install. So at least we sort of had a raster, stand by for further updates.     
#2

The new flyback is installed and now we have a good raster. This is the best picture I could get today. My pattern generator is under the knife so I'm using my vcr... and can't find my 75 to 300 ohm adapter. Next are some centering and linearity adjustments to perform     
#3

Just in time for Saturday morning, It's Howdy Doody Time.
#4

So I have things cleaned up a little bit now. I still don't have my pattern generator repaired but this is where we sit at this point. I'm having trouble centering the picture. This is as good as I can get it with the centering magnets and horizontal adjustments. Checking B+ it's good through some areas of the chassis, but in others it's 20 volts low. Time to start testing and seeing what's dragging it down. Also I need to go back and double check component values as I had a bit of an issue regarding the resistors when I started working on the board    
#5

Almost there!! Vertical linearity, size and centering looks pretty good. You are right, Horizontal linearity, centering, and / or drive is at an issue. There is often a cap in series between the horizontal yoke coils and the flyback Check thqt. Also check the boost voltage if you have a meter that can measure it.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55
#6

A small update dealing with trying to find the cause of lack of screen width on the right side. I've confirmed values of components I installed restoring the sweep board. A couple things I noticed... I failed to replace 2 silver mica caps in the 6CG7 horizontal oscillator circuit. My brain thought they were ceramic disc. I probably should change them. Also I missed the resistor at the base of the H.V. rectifier tube, and it reads high, so that will get replaced. I'll also replace the resistor at the horizontal width switch as it is original as well. And MrFix55, there is no capacitor at the yoke however there are two resistors. I suppose I should check these. My thought process is that not filling the right side of the screen can be caused by the horizontal output tube, or circuit. New tube did nothing, so it,s off to the circuit. I'm also planning on running the chassis on the bench with yoke hooked up and H.V. lead in a glass jar. It'll make voltage checks easier
#7

I wouldn't mess with the mica caps or the HV resistor. The resistors in the yoke are for damping the vertical windings. The most likely cause is the resistor on the width switch or HO components. Did you replace the HOT cathode resistor?
#8

Bob, I was so focused on the sweep board that I missed the resistor on the width switch. I had to replace the HOT as the original was smoked, and left the resistor that came with the replacement installed. It is a Triad brand. This weekend I'll replace the resistor on the width switch and then if it doesn't help, start running voltage tests




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 45-6365 Universal IFT Instruction Manual
The Philco Parts Catalog for 1942 shows it as usable for 175 kHz, 260 kHz, and 465 kHz. The instructions will show how t...DaleHCook — 11:19 AM
Stromberg Carlson 1500 Squeal
Hello Rob, I agree with you—I have one here at my house that I need to check out. It’s way over-engineered just to make...radiorich — 11:05 AM
My Atwater Kent 84
Well getting around to restoring my AK84. Mike was a big part in me being able to snatch this one a few years ago. I won...462ron — 10:57 AM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
The engine is a B&S 23 inch cast Iron holds 2 quarts of oil. The Generator is a 4 pole 1800 rpm mine was made in 195...David — 10:51 AM
Philco 45-6365 Universal IFT Instruction Manual
Dale: Modified topic as suggested. It is not for a specific project. I found it in a box of stuff I recently purchased...GRG — 10:34 AM
Plug Voltages Needed For A 1943 CRV-20130 Power Supply
That looks a lot like an aircraft connector of some kind ... That is a MIL-5015 style connector, used in a wide v...DaleHCook — 10:19 AM
Philco P45-6365 Universal Transformer Instruction Manual
I would suggest changing the topic from "P45-6365 Universal Transformer" to "45-6365 Universal IFT."...DaleHCook — 10:08 AM
Stromberg Carlson 1500 Squeal
And life just keeps getting more complicated. By dconant. Dittos'Jimradio — 08:01 AM
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

[-]
Who's Online
There are currently 1374 online users. [Complete List]
» 1 Member(s) | 1373 Guest(s)
Avatar

>