atkelar | Workshop Project #12 - Tektronix 521A PAL Vectorscope @atkelar | Uploaded December 2021 | Updated October 2024, 6 minutes ago.
This one took a bit of time to complete; the process of cleaning and fixing went reasonably well, but during the calibartion part, I did run into two problems that were hard to find... and both were "self inflicted" type of problems. Whoopsie!
Why did I get a vectorscope? Mainly because the color signal on PAL (or NTSC) is encoded in a rather strange way to be compatible with black and white TVs of the olden days. In order to validate that any PAL video source - including my test pattern generator - outputs a proper encoded color signal, I needed a proper way to visualize that encoding: enter the Vectorscope.
It might seem like a weird choice to use the same pattern generator for test signals TO the vectorscope that I needed to validate in the first place, but the signal levels are adjusted with a regular scope and then, the color information can be tuned from the calibrated vectorscope. It worked out surprisingly well indeed.
0:00 Intro / Overview Backstory
1:37 Delivery / Disassembly / Obvious Problems / CRT Removal
2:40 Plastic Clips / PCBs
3:42 High Voltage Box / Selection Buttons / Mains Transformer
5:05 Front Panel / Stuck Screws / Wire Loom and Base Plate
6:15 Painting
7:10 New Mains Connector / Selection Switches
8:07 Phase Control Knobs / Potentiometers
9:48 "Calibrated Phase" Assembly
10:30 BNC Connectors / High Voltage Box / Back Panel
11:50 Mains Transformer and Power Switch / Electrolytics / Transformer Check
12:40 DC Filter Caps / Line Selectin Switch
13:33 Front Panel Mounting
14:30 CRT Case / Front Panel Controls
15:58 CRT / PCB and Wire Loom Connections / Fuses / Power On!
16:52 Calibration Starts! / Graticule Light Issue and Fix
18:20 Beam Focus? CRT Issue! / Adjustment Issues?
19:42 Troubleshooting #2: Reference Signal Amplifier
20:30 Calibrated Phase Adjustment, Issue #3: Carrier Sync!
22:48 Final Presentation / Credits / Outtake
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
The Model 521 on TekWiki: w140.com/tekwiki/wiki/521
You can support me on Ko-Fi: ko-fi.com/atkelar
This one took a bit of time to complete; the process of cleaning and fixing went reasonably well, but during the calibartion part, I did run into two problems that were hard to find... and both were "self inflicted" type of problems. Whoopsie!
Why did I get a vectorscope? Mainly because the color signal on PAL (or NTSC) is encoded in a rather strange way to be compatible with black and white TVs of the olden days. In order to validate that any PAL video source - including my test pattern generator - outputs a proper encoded color signal, I needed a proper way to visualize that encoding: enter the Vectorscope.
It might seem like a weird choice to use the same pattern generator for test signals TO the vectorscope that I needed to validate in the first place, but the signal levels are adjusted with a regular scope and then, the color information can be tuned from the calibrated vectorscope. It worked out surprisingly well indeed.
0:00 Intro / Overview Backstory
1:37 Delivery / Disassembly / Obvious Problems / CRT Removal
2:40 Plastic Clips / PCBs
3:42 High Voltage Box / Selection Buttons / Mains Transformer
5:05 Front Panel / Stuck Screws / Wire Loom and Base Plate
6:15 Painting
7:10 New Mains Connector / Selection Switches
8:07 Phase Control Knobs / Potentiometers
9:48 "Calibrated Phase" Assembly
10:30 BNC Connectors / High Voltage Box / Back Panel
11:50 Mains Transformer and Power Switch / Electrolytics / Transformer Check
12:40 DC Filter Caps / Line Selectin Switch
13:33 Front Panel Mounting
14:30 CRT Case / Front Panel Controls
15:58 CRT / PCB and Wire Loom Connections / Fuses / Power On!
16:52 Calibration Starts! / Graticule Light Issue and Fix
18:20 Beam Focus? CRT Issue! / Adjustment Issues?
19:42 Troubleshooting #2: Reference Signal Amplifier
20:30 Calibrated Phase Adjustment, Issue #3: Carrier Sync!
22:48 Final Presentation / Credits / Outtake
Music:
My Train's A Comin'
Unicorn Heads
(YouTube Audio Library)
The Model 521 on TekWiki: w140.com/tekwiki/wiki/521
You can support me on Ko-Fi: ko-fi.com/atkelar
