I picked this up cheap recently. The packing job was ridiculous - 6 or 7 tightly nested boxes. Kinda like a "blooming onion".
http://www.bobandersen.com/images/LCG-400/LCG-400%2001-01.jpg

I've never used one before, but it looks like a very cool device.
http://www.bobandersen.com/images/LCG-400/LCG-400%2001-02.jpg

Unfortunately, I detected the nasty stink of burnt electronics shortly after powering it up. I popped it open and discovered a fried tantalum capacitor.
So far gone I can't read the value :(
http://www.bobandersen.com/images/LCG-400/LCG-400%2001-07.jpg

http://www.bobandersen.com/images/LCG-400/LCG-400%2001-08.jpg


Anyone know what the correct value is for C824 in one of these ? The one right next to it is 4.7uF @ 25v so I figure that's a good guess.

-

I've got one of these here at work. It's been sitting on the junk pile out in the garage for a while now. I'll grab it and check the value of the cap for ya.

You are correct. Both caps are 4.7 @ 25.

Thanks! I popped a new one in and no luck :(
I do have a clean +5 VDC going to all the logic ICs and the clock oscillator is running, but I'm not finding any signal beyond the stuff right around the clock.

When you say it's sitting on the junk pile, do you mean it's going to be thrown out ?

When you say it's sitting on the junk pile, do you mean it's going to be thrown out ?

No we hung onto it as a rainy day project. It's full of bad caps. I'll look around and see if I can find the service manual. If I find it I'll copy the schematic for ya.

Thanks!

IIRC, Leader used ICP's as fuses in some of their instruments. I've got a Leader Audio Generator and FM-Multiplex unit that both use ICPs. I was surprised to see them - ICP-N35 in one unit, not sure what the ultiplex unit uses. Hitachi also uses them in their Oscopes - my V1050 has two.

You might check to see if you have a bad ICP - it looks like a two legged plastic transistor and will only have the suffix marked on it. Other than tha, check for your analog voltages - +/- 12 or 15 Volts typically.

Leader makes great stuff - Stereo manufacturers required Leader equipment in their warranty stations - that's how I got mine, form a closed Panasonic/Technics dealer. You'll also like the availability of parts - others put custom stuff in their equipment, but leader used standard stuff, unlike Tek and HP.

CHeers,

Thanks for the advice. I just picked up the service manual today and will start checking out the power supply first. I suspect that shorted out capacitor took out something else like an ICP.

I've got pretty much 0 on the +15 and -15 volt rails. I disconnected all the leads to the power supply and it rose up to +/- 15.
I threw 250 mA dummy loads on the PS board and it's putting out a clean +/- 15 volts. Nuts :( Now I have to go digging through the other boards!

While testing the boards, I had two more tantalum caps pop :mad: So out they all have to go - all 81 of them :sigh:

If you go back with Tantalums, up the voltage rating, and go with Kemet brand caps - the only ones I've found to be consistently reliable. 50V tants are cheaper these days - used to be big bucks for tantalums above 35 Volts or 22uF.

If you go with electrolytics, go with a low-ESR, low impedance cap - Nichicon PJ series (Mouser has 'em) have worked well for me in Tek O'scopes. 4.7uF @ 50V will set you back about a quarter each. 81? ...only 16 cents each.

Cheers,

You know, looking at your pix of the innards, it looks a lot like my Kikusui equipment - right down to the zero ohm jumpers and markings. I wonder if Kikusui and Leader were ever one in the same? If so, you'll find it easy to work with and troubleshoot.

Heck, even the knob (Variable Composite output) looks like my Kikusui O'scopes position knobs!

Cheers,

Thanks for the tips - I ordered some Kemet brand tantalums from Mouser. I hope to have them by the weekend.

It's certainly easy to work with. Few, if any, proprietary parts, and it's all clearly labeled. Also, it uses single sided boards.

I finally finished replacing all those nasty tantalum caps and it works :banana:

http://www.bobandersen.com/images/LCG-400/Lcg-400-02-03.jpg

A few of the patterns are off a little, but the calibration procedures show how to fix them up. The circle should be centered better in this case.
http://www.bobandersen.com/images/LCG-400/Lcg-400-02-04.jpg

http://www.bobandersen.com/images/LCG-400/Lcg-400-02-05.jpg

This is what the optional multi-burst module puts out. I'm guessing it's used to test bandwidth ?
http://www.bobandersen.com/images/LCG-400/Lcg-400-02-06.jpg

These is an RF output on ch 5/6 in addition to the composite output but it seems a little weak. There's another version that does channels 3/4 which I'd rather have. We still have a local analog broadcast on channel 6 that interferes with the test pattern if I go through the antenna terminals. Perhaps I'd be better off feeding the composite into a Blonder Tongue modulator and then into the set :scratch2:

Here it is on an Admiral chassis tuned to channel 5. Now, I can clearly see that the horizontal linearity is way off :yes:

http://www.bobandersen.com/images/LCG-400/Lcg-400-02-09.jpg

http://www.bobandersen.com/images/LCG-400/Lcg-400-02-10.jpg

That's a nice generator. More bells & whistles than my Leader LCG-396.

That multi-burst pattern looks similar to the "multiburst bar sweep" pattern from my Sencore VA62A, which just came up in the color forum. I hadn't tried that before (the VA62A is sick), but here's what the manual says about the pattern:

"The multiburst bar sweep pattern is used for troubleshooting or aligning the luminance circuits in a TV receiver or VCR. The pattern's main use is to isolate video problems related to frequency response. This pattern also provides a reliable method to align the video IF stages of a receiver for the best video frequency response with minimum picture distortion."

Just flipping around other sections, the manual also describes how to use that pattern when adjusting traps, setting purity & convergence, setting the color oscillator, adjusting color killer, probably more.

The pattern looks similar to yours, but not identical.

Phil

Thanks for the info. It's an optional plug-in unit in this generator. Looks like you can manually set the frequency for each "burst".

http://www.bobandersen.com/images/LCG-400/LCG-400%2001-03.jpg

Yes, bunches o' buttons for a multiburst pattern.

http://antiqueradio.org/art/temp/SencoreVA62AControls.jpg

Read up on what the manual says you can use it for. The Sencore manual makes it sound pretty handy.

Phil

I picked this up cheap recently...LCG400... PM me if you need an original user manual for that.

There's a GREAT book by Robert L. Goodman titled "Practical TV Troubleshooting Using a Video Analyzer", which was written entirely around the Sencore VA48 (simply the earlier version of the VA62). It has over 300 pages of EXTREMELY detailed information of pretty much every aspect of TV repair that exploits every possible use of these analyzers - including TV schematics, test points, alignment information, use of patterns, etc. It puts the Sencore manuals to shame, even though they are also excellent. This is one book you really want to find if you have the VA48 or VA62.

I have two VA62's and one VA48, also four VC93's. Waiting for a tri-state buffer chip to fix the digital meter function on one of my VA62's which originally had 3 separate problems.

Thanks to Ed, I've got a user manual :banana: Now, I can really put this baby to work!

There's a GREAT book by Robert L. Goodman titled "Practical TV Troubleshooting Using a Video Analyzer", which was written entirely around the Sencore VA48 (simply the earlier version of the VA62). It has over 300 pages of EXTREMELY detailed information of pretty much every aspect of TV repair that exploits every possible use of these analyzers - including TV schematics, test points, alignment information, use of patterns, etc. It puts the Sencore manuals to shame, even though they are also excellent. This is one book you really want to find if you have the VA48 or VA62.

I have two VA62's and one VA48, also four VC93's. Waiting for a tri-state buffer chip to fix the digital meter function on one of my VA62's which originally had 3 separate problems.

Hi Barry, I finally made it over here to Videokarma and I just wanted to add the there is a later version of Goodmans book that is written around the Sencore VA62 and also has a chapter on the VC93 VCR analyzer.

Rod

Just snagged one of these on eBay. Sold as-is, it arrived with a power light working, but no output. It needed all the tantalum caps swapped out. Found 3 shorted ones, one on each of the +5, +15, and -15 lines.

Almost all were the 4.7/25 blue ones, which got replaced with 35V units. Handful of other values scattered around, as well. A couple nights on the bench and almost a hundred new caps later, the unit now pumps out video! Nice and stable, and looks picture perfect on a WFM/vectorscope.

Is there a .pdf of the manual available anywhere? Particularly interested in adjustment procedures for the circle roundness/size, as it seems a bit off.

Anyone know the type numbers for the power supply rectifier diodes? Mine look a bit toasty. 2 different types. I figured I could just use 1N5408 and 1N4007, but just curious. Would like to see the schematics for the different options, as there are several unpopulated BNC cutouts on the rear panel, and several areas of unstuffed PCB.

Mine has a "400-01 Video Swemar Unit" installed, rather than the multiburst. Is the multiburst actually a plugin? This thing is hardwired into the unit, doesn't look to be user swappable.