sweep generator models??

[sansui2000A]

Does anyone know the brand/model generator for the older 21-23 Mhz I.F. I never seem to see them on ebay.

[jeyurkon]

The Hickok 610-A for one. It's marker frequency range is 20-30 MHZ and 30-40 MHZ. With an external marker you can go 1MHZ-250MHZ. Or so says the manual.

John

[Don Lindsly]

Simpson Genescope, RCA (popular, but awkward), Jackson, GE (rarely seen) and Philco 7008 will also get you there. The Philco and Simpson have built in scopes. The RCA and GE rely on an external scope.

There are many others as well.

Don

[Penthode]

Hi There. I am new to this forum. However I have been repairing old TV sets for more than 40 years. I have acquired and dispensed with many sets over the years and now only have one: an RCA 8-T-243.

There are some fantastic buys on eBay. For sweep alignment, I use an HP 8601a sweep generator. It is top quality and can be used to sweep align TV sets and even AM Radios. When it was new in the '70's it must have cost about $10K. I bought mine on ebay a few years ago for $35.

I also bought an HP 8600 marker generator for $30 on ebay. It is a frequency counter/marker to be used in conjunction with the 8601a. With it I can accurately adjust traps.

It is amazing that this sophisticated equipment I could only dream of years ago one can now buy for so little.

[sansui2000A]

I'll keep a look out for those HP models. Most of the HP equipment has been owned by companies that send it out for calibration each year and is most likely to be more accurate than the older TV based test equipment.

[Adam]

Doing the IF alignment is something I also decided I wanted to learn to do this summer. So I just picked up a set of the old RCA equipment: WR 39C "television calibrator" marker generator, and WR-59B sweep generator. The sweep generator hasn't arrived yet, but it looks from the manual for the other unit that these should be able to work on both older - lower, and newer - higher IF frequencies. I picked up two units which both still had the probes and manuals, hopefully increasing the chances that I might actually get them to work. I went with the RCA because I really liked my WR-64B RCA color bar generator, it seemed to me to be a step up in quality compared to a lot of my other test equipment, and it's still working having done no repairs to it.

[zenithfan1]

You should also pick up a frequency counter to make sure the generator is producing the proper frequency, they are way off sometimes.

[jshorva65]

Originally Posted by zenithfan1

You should also pick up a frequency counter to make sure the generator is producing the proper frequency, they are way off sometimes.

I'll have to second that suggestion! Get the Manual for your Sweep Generator / Marker Generator and use the frequency counter to check its Calibration.

The Eico Model 369 is the best combination Sweep/Marker unit I've found (except that you'll need to make sure the special RG-22 Twin-Axial cable assembly is included with the unit when buying a used one, since the correct cable and connector for making a replacement can be hard to find). If you can get the Eico Model 368, there was a project article in the April, 1969 (IIRC) issue of Service magazine for upgrading the 368 (which uses more readily-available test leads) by adding a Marker Adder circuit to convert the 368 from its stock Pre-Injection Marker configuration to the better-performing Post-Injection setup of the 369. I still have a can of the 3-page article from Service.

The Philco model 7008 with the built-in scope is also excellent, but suffers from the limitations of a Pre-Injection Marker configuration and a few other minor trade-offs such as oddball test lead connectors (not a problem if the original leads are included with it). The built-in crystal calibration feature, the best dial vernier I've ever used, and remarkable frequency stability once it's calibrated make its marker generator remarkably accurate, precise, and stable. The Manual is a must-have (available from A G Tannenbaum) and features a fantastic section on using the crystal calibrator in conjunction with the dial vernier to interpolate to an accuracy equivalent to the 0.005% of the crystal calibrator.

As for my Top Three picks for Early B/W Alignment gear, I would list them as follows.

1 -- Eico 369 (with manual, original leads and crystal(s)) paired with a good Scope and Frequency Counter.

2 -- Eico 368 (with manual, original crystal(s), and Service upgrade installed) paired with a good Scope and Frequency Counter.

3 -- Philco 7008 (with manual and original leads). Scope optional (external scope required for displaying FM Discriminator "X" pattern instead of the standard "S" curve). Frequency counter needed for initial Calibration only.

Note: The Philco 7008's Marker Oscillator, Crystal Calibrator, Dial Vernier, and Interpolation section of the Manual may be used in conjunction with a Spreadsheet program such as MS Excel to create a Dial Settings chart for the unit. With such a chart, the Vernier settings corresponding to often-used marker frequencies may be calculated after the Vernier positions for each of the Calibration Points listed in the Manual are entered and an Interpolation Formula written into the Spreadsheet. The resulting populated Spreadsheet may then be formatted for printing, printed, and affixed to the top of the Philco 7008 case for Reference.

Here's a screenshot of the Spreadsheet that I used for creating my Dial Settings Chart. (References in "LOC" column are to Alignment points of RCA 630TS and "clones" by Fada, Crosley, Air King, etc.). We tend to service more 13-channel RCA-type sets such as KCS-20, KCS-21, KCS-26, and licensed "clones" than any other models, and the second most-frequently-seen chassis is the Dumont RA-103 / RA-104 and its "clones" by Crosley, Stromberg-Carlson, etc.

[Adam]

That Philco unit sounds interesting.

What's nice about these RCA units is that you can use them for both the newer and older IF frequencies, and with the marker-adder you can inject the markers after the set already demodulates the sweep signal. The downside is that you have to use 3 separate units, and a scope, and a bias supply, and another signal generator if you want to see 2 markers at once (you can use the crystal oscillator in the marker generator to get 2 markers that are spaced either 2.5 or 4.5MC apart), then add in a frequency counter to check all those signal generators, and you have to find room for 7 different pieces of equipment on the bench to do the alignment.

Has anyone out there tried any of the other units that do the 24MC IF, like the GE or the Simpson?