4032E Build

[horizonsound]

There was quite an audible What The F>>! heard by the neighbours this afternoon.

I took Andy M's advice, and probed around T1 output Pin 6. Sine wave present (hmmm). Well, that was strange, so I moved on to T8 pin 6 output of the 5534 and again, sine wave present. At this point, I'm completely baffled, as the next point would be at the patchbay, but nothing!!

There was only one component between the two. R57 (47ohm)......

And there it wasn't. Both cards.... missing R57.

Installed a resistor in both and wow!! instant success. Quad buss now passing through the 26 cards!!!!

Test points on schematic


Probing T1 - no need for soldering an extension wire, as they were accessible. You can see R57 missing on both.


R57 missing


Console stand being painted


Studio looking empty


Moving in


Fired up.

[waltzingbear]

ah, the little things
:-)


Cheers
Alan

[amillar]

Brilliant!  I'd have never guessed that one...

[horizonsound]

I know. It’s so absurd, you would never suspect it as a first point of “failure”.

Next job is the 82E20 VCA card, which had some shorted out BFR39 / 80 transistors, that smoked up the room when the main fusing resistors lit up.

[jimlfixit]

Hi Anthony
If there is a short on the patchbay, it would most likely be between the ring (cold) to the screen (as they are close together on the jack) and probably a result of too much solder being applied to the ring terminal which somehow shorts to the screen terminal in the patch jack and could be difficult to spot until you test the wiring and pull your hair out wondering what it is (I have had this on a few occasions before over nearly 40 years but, when I found it, I learned the lesson and try to prevent it these days with a visual inspection as I go along and before too many things are plugged in, which complicated matters further.

Sorry I haven't got back to you yet about patchbay jacks etc. I will make a note to contact you within the next few days via email. Been very busy here with various issues (work, domestic etc).

Regards from Jim Lassen.

[horizonsound]

It's been a little while since the last update.
Now the console's in a condition where I can nut out the smaller problems.
So far it's been a lot of 5534 op amp, J112 FET, 212 problems, mostly on the logic cards.
Had a 2151 blow out as well.
Getting the channel extender has sped up the progress.

Have picked up non-functional 5" CRT, which is not the motorola M1000, but a (JVC) ME-561EZ, possibly a local replacement - if it had spent it's life in Japan.

Notice that phosphor burn in!! Would be cool to get this working again.

Edit : A bit of progress on getting the screen working. Think I might have the Atari connected permanently!
Tasmanian Oak arm rest coming together today.

Anthony.

[waltzingbear]

I would recommend going to LCD

the old school video monitor has a flyback coil and attendant noise is generated by it and coupled into the desk. Its not much but its there.  Get rid of it.

and lower the power consumption and heat generation.

Cheers
Alan

[horizonsound]

You are correct around the potential of additional noise, though the power consumption is actually quite minimal. 12v at around 600mA. I’m running it off a plug pack.

Seeing as I’ve not attempted a CRT Tv repair since I was 12, this is more for the fun of it.

Anthony.

[amillar]

When the original monitor design went obsolete sometime in the 1980s I had the delightful  job of trying to find a low enough noise replacement. Complete pain in the backside. Absolutely put in an LCD!!! Otherwise unless you're REALLY lucky you'll get 15.625kHz coming out of all orifices. Because (nerdy fact) it's mostly magnetically coupled in to the desk it's almost impossible to avoid, hence the mu-metal box around the monitor (which helps a little tiny bit).

The monitors in pre ?1985? desks are surprisingly good (but not perfect). It was a real shame the manufacturer of them changed the design, I vaguely remember it was because the CRT they used went obsolete.

What you need is some software that makes an LCD monitor display look like a slightly wobbly CRT 

Cheers,

Andy

[jimlfixit]

I have seen the posts on the inboard 5" (I think) monitor in the console.

If this is of any help, the internal (within the console) wiring just consisted of a 75 ohm minimal small diameter coax cable plus a 2 core grey cable (0v, plus 12v (I think). The whole loom was (or should be) protected by a braided screen at both ends to 8 way round BICC conectors and screened at the console connector panel. After that it went to (or rather came from) the 691 computer rack.

PS: Is it just me or can anyone access and see your pictures Anthony as they ALL seem broken and unable to see now (they were fine before)?

[horizonsound]

Hi Jim,

I think you are correct on the cable. Standard 75ohm for the composite, and a 2 core + shield for the power. The shield terminates to the frame at the TV end, and carries 0v and 12v DC. 8 way BICC Trident Series connector

All the photo links are to my studio facebook page and should be public. I can still see them in the posts here, but that may because I am still logged in to facebook.

https://www.facebook.com/Horizon-Sound-201286016566616/

Anthony.

[horizonsound]

I was given an awesome birthday present yesterday - a 3D printer - so no more relying on the brother in-law.

Thought I might go back to the VU meters and print out the new design for the AL29WF adaptor.

The test run came out far better than I expected. The finish is beautifully smooth as well. It snaps in perfectly to the SSL fascia plate, and the AL29WF sized meter (hairball in this instance), clicks in easily behind it. No fiddly screws necessary. I have a PCB designed to mount behind it, that will have integrated VU lighting LEDs - if you don't want the light box-  along with status LEDs, and connected via the standard 10 pin IDE connector.
I will run off a full bank of 8 adaptors in black, over the weekend.

Lastly, the mini TV is fixed. A basic recapping exercise.

Anthony,

[radardoug2]

Ah, nice to see a craftsman at work, but I'm with those who say change that monitor. There are lots of little screens that will take video direct. But well done on the monitor mend. And please continue with the thread, its lovely to watch, but I'm glad its not me doing it!

[horizonsound]

Completed the Tasmanian Oak trims. Looking nice!
Removed the BICC 8 pin to the mini TV, and added a 3D printed block with power and composite video connector.

Seems like it will be a long wait for the next 16 modules to complete this.

If anyone has a spare bucket (frame only) and wants to part with it, hit me up.

[horizonsound]

Hi All,

First of all, I'd like to say thanks to everyone that has helped me along the way this year. Your advice has been extremely helpful and appreciated.
I had not planned on building a 4000E at the start of the year, and kind of fell in to it, but with no regrets.
The process has really pushed my knowledge of electronics.

A small xmas present to myself, I've picked up a G series computer with TR, 8" and 3.5" drives. Bypass unit is on a slow boat out of Japan.
First challenge is to put together a PSU for the computer. This one is a little more complex than the main console PSU!!!

It will be a week at least before it can be powered up, as the computer did not come with the main PSU connecting cable. ITT trident parts always seem to have a week lead time...

As it is a G series 4100A processor, the 3.5" drives cannot be used at this stage, and I am also waiting on an 8" program disk.

Anthony.