Heath IG-18 Repair/Restoration

[MED6753]

Great job as always. Reminds me I must finish off my Tek 321A

Well, get to it. Need an engraved invitation?

[mnementh]

I have that 2nd HeathKit IG-4244 scope calibrator still needs going through... and that HP 6205B, and the Harrison single-output unit... and the 2465s... and the V-212 still needs a bezel... and a shedload of crap needs to shuffle off to fleaBay...

But I must be having some sortof tinkerdwagon mid-life crisis... I'm just completely out of GAF. No idea what the actual fuck.

mnem

Bored Dwagon.png

[vk6zgo]

I have that 2nd HeathKit IG-4244 scope calibrator still needs going through... and that HP 6205B, and the Harrison single-output unit... and the 2465s... and the V-212 still needs a bezel... and a shedload of crap needs to shuffle off to fleaBay...

But I must be having some sortof tinkerdwagon mid-life crisis... I'm just completely out of GAF. No idea what the actual fuck.

mnem
Bored Dwagon.png

There's a lot of it going round.....

[bd139]

But I must be having some sortof tinkerdwagon mid-life crisis... I'm just completely out of GAF. No idea what the actual fuck.

I'm there as well if it's any consolation. Zero motivation at the moment.

[MED6753]

Geez.....are you guys TE addicts or a mouse?

[mnementh]

mnem

[bitseeker]

Winter is coming. Must be hibernation instincts.

[MED6753]

Today is calibration.

The calibration itself went fine with no issues. I used the 7904 because I could also verify how accurate the frequency setting is with the switches. It's not bad. 1000Hz indicates 1010Hz. The other ranges are similar.




But we did find an issue on final check. The Sine amplitude switch .1V and lower is dead. No output however the meter does respond. So something is up the switch deck itself. See schematic. Want to lay odds it never worked and there's an assembly defect? We'll see but I don't have time to troubleshoot it today. I'll follow up.

[Cubdriver]

Winter is coming. Must be hibernation instincts.

LOL - my automatic oil delivery got screwed up and I ran out on Sunday. House got down to 56 degrees F overnight. Amusingly, the truck arrived Monday morning at 9:05, literally as I had phone in hand to call the oil company.

The cooler weather means I’ll be able to comfortably start working on room heaters - this means the HP 524C that’s been holding my bench to the floor will finally start to get some love. Will hopefully make some progress on it over the holiday weekend.

And the one thing I DON'T like about the radiant floor heating is that it takes sixteen forevers to heat up from cold. Got the boiler up and running at around 9:30 yesterday morning and it then took until six o’clock for the temp to get back up to 67*.

-Pat

[bitseeker]

Woohoo! The blue counter disguised as a shuttle craft is back.

[mansaxel]

B&O made some groundbreaking designs in speaker tech... their electronics were more style over substance. Particularly well-known for very good PA speakers which delivered clear, well-dispersed sound from very discrete enclosures, many of which were designed to not look like speakers but more like fine furniture.

They do have their place in the world... just not in most ordinary homes.

mnem

As brought up in a home full of 60's / 70's B&o gear, I have opinions!

• The electronics were about the level one could expect from domestic gear at the time, with a strong slant towards Philips solutions and hardware. But always properly made to sufficient levels. Engineered, neither 'phool stuff, nor "as cheap as possible".
• Speakers were infinite baffle -- much like Acoustic Research, of which a pair (AR-6) still is in family possession, playing 70s Prog Rock mostly (Middle Boy has a guitar and plays Black Sabbath tunes with it.) Some of them were/are really good. Quality engineering on cabinets, quality tier drivers from companies like Philips and Peerless, later Seas and Scan-Speak. One model was very close to being the next reference monitor for Swedish Radio, having beaten the Carlsson boxes in properly done blind tests, but was crushed flat by the Yamaha NS-1000M. (Most speakers are crushed flat by the NS-1000M, at least in terms of accurate reproduction.)
• The TV's were exceptional. Traditional picture tubes, but at Trinitron quality level. B&o took the best Philips could do and made it better. Also nice to look at. I still have 2 LX2802 sets with remotes waiting (forever?) to be made into one working set. One was our main TV until perhaps 2010.
• The multiroom stuff was way ahead of its time, and it's only today, with Sonos and similar, that we have something coming close. Of course now every source is expected to be a bitstream over TCP/IP, which means we've still not reached the level B&o are at.

Conclusion is, that if you look at the complete media experience, set in context of a home, B&o is certainly unique in their ability to cater for that. Thinking more about how it is used, rather than what can be theoretically attained at the cost of all other aspects like usability, integration, and so on. Much like Apple. And also like Apple, not losing quality focus: This was all done while still delivering quality sound and picture.

[MED6753]

Continuing work on the IG-18. The last issue is that the Sine is dead .1V and below.

Decided to pull the entire amplitude switch assembly and compare it with the assembly diagram. Found nothing wrong. Was built as per the instructions. No open resistors.




I went to re-install the switch assembly with the intention of doing some power on troubleshooting and discovered the problem. And it's a design issue compounded with how the resistors were mounted on the switch deck. There is almost zero clearance between the switch deck and the chassis. One resistor was mounted out a little too far and one lead was shorting to the chassis. I moved it plus installed some insulating tape and problem resolved. Sine now functions on all ranges. I verified the calibration again and it's good. So this project is now complete.

[25 CPS]

Continuing work on the IG-18. The last issue is that the Sine is dead .1V and below.

...

I went to re-install the switch assembly with the intention of doing some power on troubleshooting and discovered the problem. And it's a design issue compounded with how the resistors were mounted on the switch deck. There is almost zero clearance between the switch deck and the chassis. One resistor was mounted out a little too far and one lead was shorting to the chassis. I moved it plus installed some insulating tape and problem resolved. Sine now functions on all ranges. I verified the calibration again and it's good. So this project is now complete.

I'm glad you found the low clearance lead grounding out to the chassis problem when you went to reassemble it. But is the project complete? How about a THD+N on the sine function? It's a good reason to pick up a distortion analyzer or a low frequency spectrum/dynamic signal analyzer so see how pure the sine output is.

I'm not stirring the pot with suggesting getting more equipment, am I?

[MED6753]

The spec'ed distortion for the Sine is 0.1% from 20Hz to 20kHz which in today's world is kinda crappy. There is a modification kit available to improve it and I'm considering getting it.

https://www.ebay.com/itm/154285948636?_ ... %7Ciid%3A1

[Cubdriver]

I'm glad you found the low clearance lead grounding out to the chassis problem when you went to reassemble it. But is the project complete? How about a THD+N on the sine function? It's a good reason to pick up a distortion analyzer or a low frequency spectrum/dynamic signal analyzer so see how pure the sine output is.

I'm not stirring the pot with suggesting getting more equipment, am I?

The spec'ed distortion for the Sine is 0.1% from 20Hz to 20kHz which in today's world is kinda crappy. There is a modification kit available to improve it and I'm considering getting it.

https://www.ebay.com/itm/154285948636?_ ... %7Ciid%3A1

But without a dynamic signal or audio/distortion analyzer, how will you know? <imagine stick pokey smiley here>

[Specmaster]

The spec'ed distortion for the Sine is 0.1% from 20Hz to 20kHz which in today's world is kinda crappy. There is a modification kit available to improve it and I'm considering getting it.

https://www.ebay.com/itm/154285948636?_ ... %7Ciid%3A1

Begs the question why When scopes are only 3% accurate so that would make the IG-18 30 more accurate then the device you're going to be using it on

[MED6753]

The spec'ed distortion for the Sine is 0.1% from 20Hz to 20kHz which in today's world is kinda crappy. There is a modification kit available to improve it and I'm considering getting it.

https://www.ebay.com/itm/154285948636?_ ... %7Ciid%3A1

Begs the question why When scopes are only 3% accurate so that would make the IG-18 30 more accurate then the device you're going to be using it on

You want the cleanest sine wave possible when doing distortion measurements on audio amplifiers. 0.1% used to be OK 40 years ago but stinks today.

[MED6753]

I'm glad you found the low clearance lead grounding out to the chassis problem when you went to reassemble it. But is the project complete? How about a THD+N on the sine function? It's a good reason to pick up a distortion analyzer or a low frequency spectrum/dynamic signal analyzer so see how pure the sine output is.

I'm not stirring the pot with suggesting getting more equipment, am I?

The spec'ed distortion for the Sine is 0.1% from 20Hz to 20kHz which in today's world is kinda crappy. There is a modification kit available to improve it and I'm considering getting it.

https://www.ebay.com/itm/154285948636?_ ... %7Ciid%3A1

But without a dynamic signal or audio/distortion analyzer, how will you know? <imagine stick pokey smiley here>

I'll steal yours.

[Cubdriver]

But without a dynamic signal or audio/distortion analyzer, how will you know? <imagine stick pokey smiley here>

I'll steal yours.

Damn, and I stupidly gave you my address when you sent those dead caps!! <facepalm>



-Pat

[Specmaster]

The spec'ed distortion for the Sine is 0.1% from 20Hz to 20kHz which in today's world is kinda crappy. There is a modification kit available to improve it and I'm considering getting it.

https://www.ebay.com/itm/154285948636?_ ... %7Ciid%3A1

Begs the question why When scopes are only 3% accurate so that would make the IG-18 30 more accurate then the device you're going to be using it on

You want the cleanest sine wave possible when doing distortion measurements on audio amplifiers. 0.1% used to be OK 40 years ago but stinks today.

I never realised that you also got involved in audio amps, and not just audio amps but true Hi-Fi amps, but even then, checking on some Marantz amps in $1,000 bracket, the distortion figures are only 0.02%, only 5 times better than the IG-18 after many years have passed, not that much progress has been made really?

[25 CPS]

I'm glad you found the low clearance lead grounding out to the chassis problem when you went to reassemble it. But is the project complete? How about a THD+N on the sine function? It's a good reason to pick up a distortion analyzer or a low frequency spectrum/dynamic signal analyzer so see how pure the sine output is.

I'm not stirring the pot with suggesting getting more equipment, am I?

The spec'ed distortion for the Sine is 0.1% from 20Hz to 20kHz which in today's world is kinda crappy. There is a modification kit available to improve it and I'm considering getting it.

https://www.ebay.com/itm/154285948636?_ ... %7Ciid%3A1

But without a dynamic signal or audio/distortion analyzer, how will you know? <imagine stick pokey smiley here>

I fully endorse the 8903B, 200CD, and the 3562A. That's a great trifecta of equipment.
A 3585A is great for audio situations where more dynamic range than the 3562A has.

[Specmaster]

You might find these links of interest regarding the THD improvement kit and the IG-18 in general.

https://shop.heathkit.com/shop/product/ ... iga-18-2-4

https://www.la2k.no/en/hardware/heathkit/ig-5218

[Cubdriver]

I fully endorse the 8903B, 200CD, and the 3562A. That's a great trifecta of equipment.
A 3585A is great for audio situations where more dynamic range than the 3562A has.

That 3562A was the gateway drug that led me to this test equipment collecting insanity. Read about them on an audio forum, and bought it on the Bay of Bank Account Depletion. That led me to the HPA mailing list (this was before the 'K' was added), which prompted the purchase of the first 5245L counter, and it's been a steep descent into madness from there...

-Pat

[mnementh]

B&O made some groundbreaking designs in speaker tech... their electronics were more style over substance. Particularly well-known for very good PA speakers which delivered clear, well-dispersed sound from very discrete enclosures, many of which were designed to not look like speakers but more like fine furniture.

They do have their place in the world... just not in most ordinary homes.

mnem

As brought up in a home full of 60's / 70's B&o gear, I have opinions!

• The electronics were about the level one could expect from domestic gear at the time, with a strong slant towards Philips solutions and hardware. But always properly made to sufficient levels. Engineered, neither 'phool stuff, nor "as cheap as possible".
• Speakers were infinite baffle -- much like Acoustic Research, of which a pair (AR-6) still is in family possession, playing 70s Prog Rock mostly (Middle Boy has a guitar and plays Black Sabbath tunes with it.) Some of them were/are really good. Quality engineering on cabinets, quality tier drivers from companies like Philips and Peerless, later Seas and Scan-Speak. One model was very close to being the next reference monitor for Swedish Radio, having beaten the Carlsson boxes in properly done blind tests, but was crushed flat by the Yamaha NS-1000M. (Most speakers are crushed flat by the NS-1000M, at least in terms of accurate reproduction.)
• The TV's were exceptional. Traditional picture tubes, but at Trinitron quality level. B&o took the best Philips could do and made it better. Also nice to look at. I still have 2 LX2802 sets with remotes waiting (forever?) to be made into one working set. One was our main TV until perhaps 2010.
• The multiroom stuff was way ahead of its time, and it's only today, with Sonos and similar, that we have something coming close. Of course now every source is expected to be a bitstream over TCP/IP, which means we've still not reached the level B&o are at.

Conclusion is, that if you look at the complete media experience, set in context of a home, B&O is certainly unique in their ability to cater for that. Thinking more about how it is used, rather than what can be theoretically attained at the cost of all other aspects like usability, integration, and so on. Much like Apple. And also like Apple, not losing quality focus: This was all done while still delivering quality sound and picture.

Never had anything video from them. Had several pieces of audio gear over the years, and my experience as a repair tech was that while their stuff looked nice, they were not only not geared towards repair, they were in fact often designed to make it as difficult as possible. Cabinetry that assembled in weird ways, dependence upon weird bespoke fasteners where ordinary machine screws would have not only sufficed, but often served much better, access plates where none were really needed or no access plate where it was a near-obvious necessity; that sort of thing.

Also entirely too much pseudo-point-to-point; individual pots and switches with a million wires to the mainboards... and a really heinous blend of PCB and fucking wire-wrap!!!

And they def suffered from the "too complicated for its own good" engineering disease on cassette decks...

I do understand your appreciation for their analog multi-room/multi-device media delivery... even I could see that was quite sophisticated, and in a good way. I just hated working on their stuff.

Kudos on keeping the AR-6es; awesome spookers. I'll advise you to do a careful inspection of the woofers in the tower; mine have finally kakked their surrounds and will need a very time-consuming renovation. Given how dependent the sound is on the Q of those speakers in this sort of enclosure, I'd definitely want to rebuild the originals rather than risk damaging the voice coils and have to replace with a substitute of unknown compatibility.

mnem
*once proud owner of a pair of CV EL36 with V-15Bs on top*

*cups hand around ear* WHAAAAAAAAT???

[tggzzz]

Wow a Heathkit which wasn't assembled by a bona fide retard. Nice catch!

I've just repossessed the Heathkit AR2000 I built with my father in '71. I ought to have a look inside.

I stuffed the boards during the Christmas Holiday, he checked them when he came home. ISTR buying a decent 25W Antex soldering iron to do it.

I don't recall the AR2000 so did some researching. What an unusual stereo receiver. AM/FM plus SW bands. I built my first Heathkit in 1970 but I don't have any catalogs from that time frame. But I do have an extensive collection of catalogs starting at around 1975 and I don't ever recall seeing it. I'll have to pull them out to be sure. All references and vintage adverts that I found reference Heathkit UK only which made me suspect that it wasn't available on this side of the pond. I did find the schematic so I looked at the power supply and it could be wired for either 120V/240V so I guess at one point it was available here.

I've put a mini-teardown at https://www.eevblog.com/forum/repair/he ... msg4543538

The AR-2000 had respectable specs for the time, and we never noticed any limitations.

Most things back then were 120/240V, so I don't regard that as surprising.