Tannoy Reveal 6D

[Khron]

Re: Tannoy Reveal 6D

"Bypass switch", as in, the mute switch? Or...?

[micdim]

Re: Tannoy Reveal 6D

"Bypass switch", as in, the mute switch? Or...?

Yes the mute switch. Thanks!

[Khron]

Re: Tannoy Reveal 6D

It isn't anything special, nor does it need to conduct any meaningful amount of current. Your biggest concern is to find something that's mechanically compatible, so... You or your tech will just need to remove the little front plate and start digging through parametric searches on parts distributor websites, I'm afraid.

[micdim]

Re: Tannoy Reveal 6D

It isn't anything special, nor does it need to conduct any meaningful amount of current. Your biggest concern is to find something that's mechanically compatible, so... You or your tech will just need to remove the little front plate and start digging through parametric searches on parts distributor websites, I'm afraid.

Yes I will will convey this to my New Tech. My previous Tech doesn't seem to want to do the research work.

Thank you!

[midibob]

Re: Tannoy Reveal 6D

Well, after starting this thread all those years ago my other 6D failed the other day with the speaker cone almost jumping out the box and a loud hum.

On strip down I found the -15v supply resistor had failed (220R 5W). When replaced I noticed it was running far to warm for my liking. This was due to the digital board which I don't use so it was disconnected as I couldn't be bothered to fault it.

All now fine.

[Valden]

I've just completed my latest repair of a Tannoy Reveal 6D monitor. It was making a crackling noise on start-up, which would last for ten or twenty minutes, if not more. The audio output would be cracking too. But it would go away and the sound would eventually be fine. I suspected capacitors. (Edit - my kids told me it was making a very annoying high pitched sound as well, but I couldn't hear that. I'll ask them if it's gone.)

Upon disassembly and diagnosis with an audio probe and separate amplifier I found that the crackling sound was not present at the output of the filter board or at the input to the amplifier ICs on the power board but was present at output pin 10 of both amplifier ICs. So, it was likely to be a problem with the power supply on the board, rather than one of the amplifier ICs. Probing with a multimeter showed that many of the electrolytic capacitors were even weirder than they usually are when assessed while mounted. I removed all of the electrolytic caps (except the two, big, 10,000 uF ones). About 70% of these were dead or way off. Two of the resistors (no 19 and 21) were also out of spec. I replaced all of the small electrolytic caps and the two resistors at a cost of about $5. This Tannoy Reveal 6D monitor is working again. Yay.

But the main reason for writing this note is to describe the disassembly and reassembly process, which is tricky, given how there are hidden screws underneath the heat-sink and the transformer. Dealing with these could be fun - or not. Let me describe what you will find and how you might proceed.

There is an aluminium plate onto which all of the monitor's main elements are mounted. This is held into the wooden speaker box with six, 3mm hex cap screws.

The power board is mounted onto the plate with five screws with flat, countersunk Phillips No 2 screws, which are hidden underneath the heat-sink.

The large heat-sink is screwed onto the plate with eight screws from the inside. Seven of these are round headed Phillips No 2 screws. Some are hard to get at due to the power board. One of the eight screws is a flat, countersunk screw with a Phillips No 2 head. This one is hidden underneath the transformer. (Note that it has the same thread and head as the screws for the transformer, but is shorter than those four screws.)

The transformer is mounted onto the plate with four flat, countersunk screws which have Phillips No 2 heads. These act as bolts, onto which 7mm nuts are fitted from the inside. The top two of these bolt/screws are hidden underneath the heat-sink. As such, if the heat-sink is still in place, they can't be held with a screwdriver while the nuts are loosened. It becomes a chicken and egg situation as you try to remove either the heat-sink or the transformer, so that you can remove the power board.

First, undo the seven round headed screws which hold the heat-sink onto the plate from the inside. The last, hidden screw will still hold the heat-sink onto the plate, but it will pivot. Be careful that its pivoting action does not damage switches on the filter board. To pivot the heat-sink so that the screws for the transformer are Revealed (the real reason for the monitor's name!) remove the power cable socket and the power switch. Pivot the heat sink, smearing white heat paste everywhere, then hold the transformer's screw heads with a screwdriver so the corresponding nuts can be loosened. Or, another way could be to use a cold-chisel and hammer to shear through one or both of the top two screws that are holding the transformer on. Or use a hacksaw blade to cut one or both of them. This is what I did. First a hacksaw blade cut through half of right-hand screw, then a chisel cut the remainder. With only one partly loosened screw holding the transformer on, it could be pivoted to Reveal the last screw that was holding the heat-sink on. Ta da! The heat-sink was removed, then the power board. I left the transformer loosely connected to the plate and put it aside.

For reassembly, the best thing to do is to use strong epoxy to fix the transformer mounting screws into the plate, so they will remain still while their nuts are being tightened later. With these screws glued into place, the power board can be installed (using thermal paste for the ICs and thermal fuse), then the heat-sink can be installed (using thermal paste) and lastly the transformer. But do a brief performance check before full reassembly. Brief, to avoid cooking the amplifier ICs, which will be lightly screwed onto the aluminium plate for this test, but without the large heat-sink in place.

Or course, if you want to be able to reuse the transformer mounting screws, destructive removal is not advised.

But most of all - feel encouraged to dive in and fix your Tannoy Reveal 6D or 8D monitors. Chances are, if you're reading this you've already become adept at repairing them. :-)