View Full Version : Packard Bell 17VT1


Winky Dink
06-26-2017, 11:37 AM
Subject: CRT Testing

I would never have thought of acquiring this set, but a friend (Iíll call him Philo) rescued it from someone who was putting it out with the garbage. He plugged it in and the screen lit up, so he shipped it to me. For free, Iíll try to put the set in working order. Philo will get a kick out of that.

Iíve pulled the chassis, and all the parts are there. The only shipping damage is one broken tube and a broken escutcheon, both easily repaired or replaced. And the yoke is loose on the CRT neck.

My next step will be to check continuities to ensure other significant components arenít dead. Iíve tested the tubes, including the CRT.

Iíd like an experienced person to assess my test results on the 17AVP4. With a Beltron 8080A, 6.3 heater volts:

No shorts.
Ten seconds to reach 0.45mA.
After four minutes, it reaches 0.55mA or maybe 0.65mA.
Interrupt: Current immediately decreases, reaching almost zero in seven seconds.

https://c1.staticflickr.com/5/4213/34739933323_7e48a1377d_z.jpg

So, before I spend any time on this set, what can I expect from the CRT?

Thanks all,
Henry

bandersen
06-26-2017, 12:35 PM
How long did you have thee CRT running on the tester ? I like to leave them run 30 minutes to a couple hours to "wake" them up. Often emissions, cutoff and life test will improve.

Winky Dink
06-26-2017, 03:24 PM
Thanks. I only ran it five or ten minutes. I'll run it for a couple of hours this afternoon and see what I get.

Winky Dink
06-26-2017, 06:09 PM
I checked the heater voltage from the 8080A. It was probably 6.7 volts for the previous test. I adjusted it to 6.3 volts and ran it for 90 minutes. This time it took about 2 minutes to peak at barely over 0.2 mA, then slowly decreased to 0.15 mA where it stayed for the entire test period--then dropped to less than 0.05 mA in a few seconds.

Entirely hopeless? Even if it's hopeless I'm going to play with the restorer just to see if the meter and indicator lights work.

maxhifi
06-26-2017, 06:18 PM
After you let it "cook" for a while, if it's still really weak, you can also try running it at, say, 8V for 10 minutes, then put it back down to 6.3 and test it again. Has worked for me. Only time I tried "restore" was on a Trinitron, and it made it much worse, rather than better.

Winky Dink
07-11-2017, 08:31 PM
I left the instrument on for several hours and tried increasing the voltage for 10 minutes, but had little change in subsequent test results. Then I ran the restoration procedure one time. After that the test meter rose promptly to .85mA, the minimum "good" result. When the voltage is cut, it only held that current for two or three seconds. I repeated the test two days later with the same outcome. So, I'll proceed with the electronic restoration and hope for the best.

StellarTV
07-12-2017, 12:40 PM
Since you've got the Beltron, run a clean cycle on the tube. Won't hurt a thing and it's very likely to bring that tube right back, even without running a full restore cycle on it. I just can't say enough about Beltrons. :banana:

Winky Dink
07-12-2017, 05:32 PM
After reviewing my personal notes and retrieving deleted email, I now recall that I ran a cleaning cycle first without even a flicker of the lights, then did one restore cycle. That's my story and I'm sticking to it!

Electronic M
07-12-2017, 09:06 PM
I ran a cleaning cycle first without even a flicker of the lights...

That is normal. Do you have any idea how many tubes you'd need to clean at once to make all the lights in your house flicker? :D

Winky Dink
07-13-2017, 03:54 PM
If you knew me better, you’d realize that I might take down the entire power grid by changing the batteries in a flashlight. (Just ask my wife what happened the first time I tried to fix a toilet.)

Winky Dink
01-31-2018, 10:49 PM
Well, it only took me six months to get back to this. I did a quick repair on the escutcheon and reassembled it for photos.

https://farm5.staticflickr.com/4703/26103879608_115b342fb5_z.jpg

.
. It's a 1956 Packard Bell 17VT1--a cube with a rectangular CRT in front, knobs on one side, and a simulated wood finish. Chassis V8-1.

https://farm5.staticflickr.com/4666/26103879988_794e7b6d0f_c.jpg

https://farm5.staticflickr.com/4678/39944861722_be5987077f_c.jpg

Before I pull the chassis again, I have an opening question:

Should I pull the CRT first to start the chassis work?

Thanks,
Henry

kvflyer
02-01-2018, 08:46 AM
Well, it only took me six months to get back to this. ...
Before I pull the chassis again, I have an opening question:
Should I pull the CRT first to start the chassis work?
Thanks,
Henry
Henry, it would certainly make life easier. But the question is are you up to reinstalling the CRT and all that goes with it?

Your call...

Winky Dink
02-01-2018, 11:22 AM
Thanks. Did that last night. Only had to cut six (clearly colored) leads from the yoke. Yoke, ion trap, etc. stays on the neck. The yoke is loose anyway.
- Henry (formerly of Indian Head, Silver Spring, Baltimore, Columbia, and Frederick)

jr_tech
02-01-2018, 02:56 PM
Sometimes if the yoke does not slide off easily over the base cap, a little gentle heat from a hairdrier is helpful.

jr

kvflyer
02-01-2018, 03:45 PM
...
- Henry (formerly of Indian Head, Silver Spring, Baltimore, Columbia, and Frederick)

kvflyer, AKA Don Cavey. Worked C&P Telephone, Columbia, Arbutus, Cockeysville, Manor, Essex, etc. Now retired in for 15 years ... Fernandina Beach, Florida! No snow to shovel.

Electronic M
02-01-2018, 07:12 PM
Sometimes if the yoke does not slide off easily over the base cap, a little gentle heat from a hairdrier is helpful.

jr

Wrapping a thin card stock shim around the glass over the bakelite base can also help.

Winky Dink
02-02-2018, 03:25 AM
Removing the CRT with the accoutrements attached was simple. Aquadag coating (or whatever) looks intact.

https://farm5.staticflickr.com/4721/26162749018_70241da678_z.jpg

Cleaned up the chassis a bit, and now I'm checking continuities through all coils. The yoke checks out OK.


https://farm5.staticflickr.com/4620/39325331364_cbb11e86a3_c.jpg

Winky Dink
02-04-2018, 07:03 PM
Below is a photo of the wiring of one of the 'lytics. It appears to be factory-wired, but I can't reconcile it with the Sams schematic, parts list, and the info stamped on the can.

https://farm5.staticflickr.com/4704/25210208397_32efa7ca2c_c.jpg

So, please tell me that I'm reading it wrong or, if the schematic and the wiring disagree, which I should do--follow the schematic or duplicate what's already there.

Thanks,
Henry.

dieseljeep
02-04-2018, 07:20 PM
Below is a photo of the wiring of one of the 'lytics. It appears to be factory-wired, but I can't reconcile it with the Sams schematic, parts list, and the info stamped on the can.

https://farm5.staticflickr.com/4704/25210208397_32efa7ca2c_c.jpg

So, please tell me that I'm reading it wrong or, if the schematic and the wiring disagree, which I should do--follow the schematic or duplicate what's already there.

Thanks,
Henry.
The schematic is wrong!
The 6AS5 audio output tube is used a voltage divider as well. The voltages shown are way off. The voltage on the cathode should be at least 100 volts or more.
Just wire it the way you find it! It worked before! :scratch2:

Winky Dink
02-04-2018, 08:52 PM
Thank you. I'll proceed as advised and I'll keep in mind the voltage discrepancies when I get there.

dieseljeep
02-05-2018, 10:58 AM
Thank you. I'll proceed as advised and I'll keep in mind the voltage discrepancies when I get there.

The plate and the screen should read the full B+ of the set, 250 to 280 volts or so. The cathode should read 110 volts or so, to supply the IF and a few other circuits.

Tom9589
02-05-2018, 08:59 PM
The "half-circle" symbol next to the voltage readings indicate that these particular voltage readings are referenced to another point other than chassis ground.

dieseljeep
02-06-2018, 10:42 AM
The "half-circle" symbol next to the voltage readings indicate that these particular voltage readings are referenced to another point other than chassis ground.
I don't know where they referenced from, as all the components are going to chassis ground! :scratch2:

Winky Dink
02-20-2018, 12:46 AM
Regarding the Sams 6AS5 schematic error, I got the Rider schematic, and it shows the correct wiring and voltages. The voltage shown on the Sams schematic are measured from a 110 volt line, so that explains why they're all about 110 volts too low.

https://farm5.staticflickr.com/4665/26502163708_af4171595b.jpg

I'll be ready to power up the set in a few days. My concern is how to set up the CRT off the chassis. I can't imagine trying to check voltages with the CRT mounted on the chassis. I made a connector for the yoke wiring from an octal base and socket. It has plenty of extra length, but it'll be easy to shorten it. The solder connections are insulated with 1/4-inch irrigation tubing which fits snugly but slides on and off easily.

https://farm5.staticflickr.com/4757/26502161428_477b242625_z.jpg

The limiting factor is the six-inch high voltage line. I have some cable rated 40 kilovolts. The CRT is 15 kilovolts. Is it feasible and safe to splice 14 inches of that to extend the original 6-inch cable?