B&H TQ II sound volume

[Clive Carmock]

I have a Bell & Howell TQ II 16mm projector, which has not been used for around 18 months, but was used today.
It definitely needs some maintenance in the form of lubrication, as the rear take up spindle will often not engage, which I believe indicates lubrication needed on the slip clutch. Also the sound head tensioning rollers need help the grip the film. This will be some work I can do over the next week.

Where I would welcome some advice is on sound reproduction though. I have found that the volume through either the internal speaker or extension speaker is fairly low, compared to how it used to be. It is clear and intelligible, just lower in volume that I remember. Some films need the volume control set to maximum to be heard well.

The sound optics are clean. The exciter lamp is in good condition and shining brightly. The machine has been stored carefully in dry conditions with no knocks that could have put the sound optics out of alignment. I have checked the speaker connections, as originally the speaker DIN connector at the back did not form a good connection so I had replaced it with a good quality Speakon connector a few years ago.

I am wondering if failing electrolytic capacitors ont he amplifier could be contributing to this problem? Any advice welcome

[Terry Sills]

Always check the simple things first. The photo electric cell may have degraded over the years. Try replacing it and see if it makes a difference.

[Clive Carmock]

Hi Terry I see you are UK based also. Do you know of a source for the photocells used in these machines?

[Alan Paterson]

There used to be a chap called Gordon Ogbourne in Ruislip who sold spares for Bell & Howell projectors. I bought an amplifier board for a TQIII projector from him. I don't have his contact details any longer. Hopefully he's still around and can help you with parts.

[Clive Carmock]

Thanks Alan I'll see if I can track Gordon down. I'm keen to keep this TQIi machine running as long as I can. It had a new worm gear fitted by Lee's Cameras in Holborn several years ago so at least that should be good!

As this sound problem has seemed to get worse over time I have to assume it's somehign failing over time which is what made me think of capacitors. Or as Terry has suggested mybe the photocell.

[John Burgess]

Clive, worse case scenario you could change the amplifier, found this which is for a TQ111 but might be compatable. See eBay link

[Clive Carmock]

Thansk John I'll take a look - I go have the service manual for the TQII series The amplifier board looks different in there. I'll also need to locate it! The Preamp board in the TQ II is undernear the chassis, under a plastic cover with th volume, bass & treble controls, I haven't located the main amp yet

[Clyde Miles]

hi clive, sorry to chime in so late here. gordon ogbourne has recently undergone surgery for cancer again. hope he does'nt mind me saying this. i've had lots of spares from gordon, always very helpful, and he is still listing parts on ebay, best

[Clive Carmock]

Thansk Clyde I hope Gordon makes a speedy recovery. Do you know if he is cinema_paradiso on eBay? if so he has confirmed he doesn't have any solar cells for the TQ II.

Larry Urbanski might be able to help me with both.

I have found the TQII moel was actually a range of about 6 machines in the UK. My specific one is a 1655, optical only.
I have located the pre-amp board in this machine - easily found under a pastic cover on the base. I am assuming the main amplifier board is deeper in the machine maybe behind the motor? I haven't located it yet.

[Clyde Miles]

hi clive,
cinema paradiso is'nt gordon, but gordon0189gordon is. the amp is located on the very bottom
of the tq2, under the large black panel, could be the capacitors on the amp considering there age now.

[Clive Carmock]

Ah thank you I have dropped gordon a line. I have been working on the machine today - and see the pre-amp is under the machine as mentioned. The main amplifier is mounted on the inside of the rear panel of the case, so not too hard to get at, since this panel is removable.

I have however now managed to introduce a new fault! One step forward and two back. On this series machine to fully remove the back cover there is a wiring panel that contains the power inlet, fuse, 18/24 speed switch etc that that to be removed and then passed into the machine through the hole in the back panel. B&H really made this a challenge as the wires are not that long and there is not much movment to get the board through. Having managed it a few times before this time I managed to break off a wire from the speed control board - the white wire with a black stripe. It looks liek this had happened to the previous owner, as I did see a small blob of solder where it came from that is clearly not original.

Anyway I have resoldered the wire but now the machine will only run at 18 fps regardless of the position of the speed switch. All other wiring as well as the damaged one are connected correctly. However I note what appears to be a slight bulging on the capacitor C701 which is right next to the solder repair. Wondering if this capacitor was borderline and the heat from re-soldering right next to it pushed it over the edge. It's a 10uF 6.3V electrolytic, which I can easily replace if need be. I wonder if anyone with better knwoledge than me might know if this capacitor failing could cause the fault I have.

I'll try to attach a picture of the service manual section for this as well as a picture

[Clive Carmock]

I had some time to work more on this machine today and have corrected the speed problem - the variable resistor VR702 which controls the speed at 24fps was slightly oxidised - a small drop of contact cleaner and it's working perfectly again and 24fps is restored.

So just the below average volume problem to fix now

[Steve Klare]

Hi Clive,

It's a pretty common thing for an audio circuit that has been standing idle for a long time to have low volume because of oxides on switch contacts. What I've seen over the years is the volume setting needed to get adequate sound creeps higher and higher until all of a sudden you find yourself at max volume with nothing impressive coming out of the speaker. In storage it can get even worse.

I have a machine that was stored new yet dead in a camera shop from the 1970s until 2017 that was just loaded with this problem.

What you need to do is identify switches associated with audio such as an On/Off or PA/Film Sound and with the machine unpowered, work them repeatedly, more than 10 times. Audio jacks often contain hidden switches (-for example the ones that cut off internal speakers when you plug in a headphone), and you can clean these by getting the mating plug and repeatedly plugging/unplugging. I had a mute machine come to full volume once just by plugging in headphones, hearing good volume in the earpiece and then unplugging and hearing it in the speaker, too.

If you can get directly at the contacts and spritz a little contact cleaner that helps out a lot too. I've had repeat offenders that were fully reformed this way.

Am I guaranteeing an instant fix here? Absolutely not! However, I have seen this work a number of times and since it costs nothing to try, it's always worth a go, even as a first attempt before you go surgical.

I remember somebody on here working the recording key on an Elmo S8 machine 20 times before it surrendered and he got full volume back. (I have to admire his persistence: I've never seen it take that many tries myself.)

(-Best of luck!)

[Clive Carmock]

Useful advice thank you Steve. The Speaker DIN socket on this projector disintengrated a few years ago so I replaced with with a Speakon connector that also has the inbuilt switch, so that is still new, though I will check it's contacts. The lower than normal volume affects both the internal and extension speaker.

From the schematic it looks like two other mechanical switches could affect this - firstly the switch within the microphone input socket, and a switch within the main control. I will check both of these and clean.