Vintage RCA 630TS Electronic Restoration Page

PART 2: Here is the part where the following components are restored or replaced Twist lock electrolytic capacitors are restored, all paper capacitors are replaced and all defective and out of tolerance resistors are replaced. Adjustable controls are inspected, cleaned and repaired if needed, top and underside of chassis inspected for removal of dust and dirt, wires inspected and replaced/repaired and damage hardware is removed, repaired, replaced and if needed a substitute is made by me.

Underside of Chassis BEFORE E Restore

Underside of Chassis AFTER E Restore

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In this page I use reference designators like V107 and R208, these are from the original RCA Service Manual.

1. Restoration of Twist Lock Can Electrolytic Capacitors

Chassis mounted multi section can capacitors was a common place in tube television. These capacitors called twist lock consist of several (up to 4) individual electrolytics sealed in an aluminum can. Over time the aluminum oxide paste would start to dry out expand and causing an open cap which in turn can start a possible shorting the neighboring units The RCA 630TS has 6 of these can electrolytics on the top and underside of the chassis. I worked on 1 can a day, so the process took about 6 days to complete

Removal

Before unsoldering I labeled are the caps on the chassis C220-C226 as stated in RCA Service Manual. Then tagged each lead to be removed with its correct destination. Try to be neat in your writing. There are times I can't read what I wrote.
When the unit is removed from the chassis, I cut the can where the body meets the base. Then with a heat gun, heat the can and pull the can out to expose the insides. In this picture the aluminum oxide paste has dried out, indicating a bad unit.

Restoration

Holes are drilled in to the base of the can capacitor to allow leads of new capacitors to come out and be soldered on the existing lugs. Then the new capacitors are installed in a "Tinker Toy" fashion. Notice in the photo, the black bar on both parts of the can unit. This was done before cutting the can to align the can cover to the base so it can be glued back to a proper fit
The empty can covers are cleaned, and labeled. They will be set aside until the TV is operational, when at that time the will be glued back to look like the original product.
Labeling wires that connected to the multisection electrolytyic capacitors
After the leads are soldered, then use a solder sucker and braid to clear out as much solder from the chassis tabs. Straighten the tabs and pull straight out with some wiggling.



























5. Rebuilding the Horizontal Centering Control

Checking the Vertical and Horizontal Centering controls R181 and R201 respectively. R201 was not adjusting so I had nothing to lose but disassemble and open it up. Found that the resistance wire had broken off from the terminal (were spot welded on).
Centering ControlsLocated on rear left side
Notice the broken wire on right-center of Horizontal Centering R211



REPAIR CHECK AND REINSTALL

2. High Voltage Cage Electronics: Inspection and Repair/Restore

Read an article from another collector to inspect the high voltage area for burned resistors and dust buildup. The resistors needed to be replaced as their insulation was crumbling and the HV loop and other areas needed to be cleaned up.
All cleaned up, including contacts. New high reliability resistors installed. The large power resistor in the back (R209) checked good. The 500 pF doorknob capacitor was cleaned up, they are generally very reliable.

BEFORE

AFTER

The HV anode cable insulation was breaking down on both sides of the cable from CRT to HV cage. Had some 15 kV cable I had from a neon light assembly project, so I rebuilt the cable.













LEFT


 attach new cable to anode cap.





LEFT & BELOW


install other end to HV Rectifier V107 (1B3GT / 8016) high voltage output.

6. Examples of Replacing Paper Capacitors and out of Tolerance Resistors

Here is a typical paper capacitor. On the lead end there is a small crack where the wax has separated from the end cap, potentially allowing moisture to get in and damage the part. All these types of capacitors need to be replaced. They may work now but will fail anytime.

Resistors

Those made before the 1970's were basically a slug of carbon trimmed to a value and encapsulated. As time passes moisture and heat can change the value to go beyond the tolerance allowed. Resistors are checked to see if they are in tolerance range specified. This set uses mainly 10 and 20% tolerance resistors. Some are 5% tolerance, which need to be checked carefully. Most of the time I don't have to unsolder one lead to take a measurement. However especially in tuned circuits I may have to unsolder the lead due to loading.
Sample of a 100 nF paper (ABOVE) capacitor that tests bad (reads 0.96 nF versus a modern (BELOW) 120 nF ptfe film capacitor (reads 124.9 nF) to replace it. Basically the paper capacitor is open and not functioning. Moisture probably got in and separated the lead from the capacitor.

LEFT

Here is an interesting replacement at R200 (5000 ohm 5 W 10% tol). RCA used a obsolete carbon slug aka body and dot or "dog bone" resistor that says 5600 ohm at the horizontal oscillator section. It read 3900 ohms which is too low. Installed a 10 W adjustable power resistor since 5000 ohm is not standard value.

LEFT


Closeup center section of chassis showing capacitor and resistor replacements

3. Replacement of the BLEEDER Resistor Set


The bleeder resistors make up R185 (2 resistors) and R186 (3 resistors). They are located behind the power transformer in the flip open black box.They are used to both set up the voltage divider network for LV distribution (+275 V, +185 V, -2 V, -18 V) and bleed off the residual voltage when the set's power is turned off. These are power resistors from 5 to 20 watts and are custom made for the TV.
Top blue resistor has open winding at R185 common problem.













To replace bought two adj resistors and set them to spec

4. Tuner Inspection:

Remove the shield and protective cover, The contacts look clean. I used contact cleaner to remove and dust and grime .

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Completed Top Chassis E-Restore. Electrolytic cans reinserted over restored inside. HV Cage cleaned and repainted. Transformer and bleeder box repainted. Tube shield sanded and repainted. Notice that I did not redo the chassis except rub a layer of thin oil like furniture polish. I've seen some really nice chassis restorations but there are a lot of non-replaceable coils and transformers so I didn't want to risk damage.

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