L102 - no sound (First Post)

[Jeff Gascoyne]

Greetings from the UK.
Bought the organ with non-rotating tone wheel motor. Replaced motor and run capacitor having read a pertinent thread on forum.

Added about 2mL of TWG oil. Cleaned every connector and socket visible between internal units with Brasso and denatured alcohol.

Now the motor turns the generator and even runs for a few seconds after switching off.

All valves glow and if I tap the reverb unit the sound is amplified through the speakers and seems to respond to the 'swell pedal' by changing in volume.

It has been split but connectors there look good.

The previous owner said he played the organ by spinning the motor by hand to get it going.... but said in his advert this no longer worked. I believe this was the only fault he knew of.

Going to keep cleaning connectors and remaking connections as thats my knowledge limit. That and previous forum posts!

Where do you start on fault diagnosis? I'm getting those disparaging looks from my wife... but she's refrained from the I told you so!

Grateful for assistance if possible.

[Wes]

2mL of oil isn't even close to the right amount. Try 2 oz (60 ml). Also add 12 drops (about 1.2mL) to the spring-loaded oil funnels at each end of the motor.

There should be a wire leading from the preamp (AO42) to the expression pedal to the power amp (AO43). This wire is pretty close to normal audio levels. Find out if there is any signal on this wire.

Suggest leaving the organ running for at least one minute for the tubes to warm, test with the "drawbars" tabs depressed, all drawbars pulled all the way out, volume not-soft, brilliance on.

Wes

[Sweet Pete]

The run motor cap (silver rectangular can) beside the run motor ? It's well beyond it's life expectancy and needs to be replaced.
2ML is not enough oil.

[Jeff Gascoyne]

Thanks for the response, I hope one day I’ll be able to help someone in return....

Please bear with me here if I’ve got this wrong, I removed the connector from the ‘WH’ socket of the power amp. Connected a volt meter on 1v scale across the centre pin and outer tabs with the pedal fully down. There was no deflection at all.

That said the amplifier buzz goes louder as I depress the pedal. If the organ function is restored suddenly I’m going to jump a mile judging from the volume of the reverb springs.

I’ve also added oil into the funnels again and refilled the two motor oiling tubes.

Sitting at the back without the cover on I can hear the motor surging on power up. It then settles to steady revs. The valves also flash brightly for an instant, not sure if there’s anything in that.

In response to Sweet Pete, thanks here too, I put two 2.5micro farad / 440v capacitors in series to replace the resident capacitor which was not original. Not to give away my lack of knowledge but there was an absence of polarity markings on the capacitors. The symbol for a capacitor has arrows in both directions.

The previous motor had lost a lug and the grey wire was no longer connected to anything. When I turned on the organ and tried to spin it by hand it was locked solid. Without power the original motor and TWG turned easily.

The wires to the Reverb SW connector were fatigued and came off in transit. I don’t think the wires are original.

I am sorry (eyes rolling) but I have guessed the top and bottom two wire positions.

[Jeff Gascoyne]

I sense I’m out of my shallow depth here. Going to see if a local instrument/amplifier repair shop will take it on. Probably quote more than it’s worth in money terms but if it brings my sons to play music together what price on that. If a repair is possible I’ll add what details I can. 40 years since A level Physics is just too long ago....☹️

[RogerRabbit]

Hi Jeff, lets do a little troubleshooting and see if we can eliminate some things. You can download the service manual here http://dl.lojinx.com/analoghell/Hamm...viceManual.pdf have a look at the schematic on page 33.

If you hear noise through the speakers when you tap the reverb unit, then V8 and everything to the right is probably OK in the Power and Reverberation amp.

So power off and swap V8 and V6, power on and do the tap test again... do you hear the same noise? if so then both valves are probably OK, power off and swap them back, power on and tap test to make sure you are back where we started.

Next, power off and swap V8 and V1, power on, do the tap test and also try pulling all drawbars out and see if you get any sound from the manuals - this has now tried all the valves in the basic sound chain up to and including V8, but not the vibrato circuit.

See how that goes, and where in the UK are you?

roj

[Jeff Gascoyne]

Not sure if my response got sent okay. Essentially all combinations were good for the tappex Reverb unit but nothing on the keys.

I'm in Stockport.

Thanks for the valve check details I see three other valves of the same nominal type...are they next for a swap around?

[RogerRabbit]

That was a quick test for most of the valves in the dry signal path, the others wouldn't make any difference if the first three are good.

[Jeff Gascoyne]

Diagram 1-3.... if the output of the power amp is now exonerated are the next units to check the input of the power amp Side and the volume pedal?

There are grey wires which look like they have been indented from being caught by the pedal but they look intact still. Given that the buzz/hum increases in volume as the pedal is depressed are these two units off the hook?

If correct.... then next is the vibrato amp? Is this where I need to take it to an expert to identify the fault or is there a check I can perform? I only have my analogue electrical meter for voltage resistance and points dwell setting.

Meanwhile I clean things with care and try the occasional power up hoping it has undisturbed something.

[RogerRabbit]

The vibrato amp works in parallel with the dry path and is mixed at the input to V1, so if the dry path doesn't work nor will the Vib path. To eliminate the swell pedal you could jumper over the input and output of it easily.

BTW, be aware that there are lethal voltages in a valve circuit...

[Jeff Gascoyne]

Thanks for the warning. I’ve taken great care to leave the organ off for a few minutes before approaching the exposed parts.

I unbolted the pedal assembly and my son pointed out the wire was severed. I couldn’t see that only the insulation was holding it in position.

Hopefully I can get a replacement wire tomorrow. I am supposing the wire has been pulled about in the past and the pedal has pinched it at several points. Finally it has settled on one place and worked at it over time. Possibly the journey fetching it administered the coup de grace.

If this isn’t the only problem at least it’s one less.

[RogerRabbit]

If that is a white wire then that's probably the fault - sever one of those and no sound... strip it back and solder the ends together temporarily and test, I think you'll get sound. There should only be signal level voltages on that.

[Jeff Gascoyne]

I couldn’t wait so found an unshielded non coaxial replacement.

And at last sound!

Fifth from the left drawbar on the lower manual doesn’t function. The lowest A flat on the lower manual doesn’t work.

But I’m sure I’ll find a relevant post for these.

Thanks for the encouragement and information.

[RogerRabbit]

Yay! always a pleasure to help where we can :)

The drawbar probably has a loose/broken wire.

[Wes]

coax - instrument cable, rca cable, cable television cable, any of these would work if you solder the right ends on it.

Drawbar wire is probably broken. If not, just check "drawbars" switch contacts and the molex connector.