HELP! My Tascam M-216 has a faulty VU meter needle. How do I locate and diagnose the cause?

[rob aylestone]

Well, a quick reflow of the solder on the flying leads to the meter might work if yo7 are luck, but I reckon the meter has just died. You might be able to open it and fix it, but that requires some finesse and dexterity. However, if one flicks and one doesn’t, you have found the issue. Now to fix it!

 

[Steenamaroo]

hello everybody while going into diode mode and touching the meter connectors t(the bottom pins on meter board 1 and 2) i went R911/R912 (meter 2 jumped and was shaking its tail feather. meter 1 unresponsive.

but just to be sure i went closer in the circuit to the meter itself and touched the connecting bottom pins that connects it to the pcb.
once again number 2 shaking it. number 1 dead.
i guess to finnaly conclude if its the connection to the board and just need a resoldering or if its the wires inside is only possible if i open it up and do a test direct on the meter right?

Yes, that's pretty conclusive.
If your DMM moved needles but did not move the needle for the suspect meter then there's a broken connection in, or to, that meter.
Reading higher than expected resistance (in circuit) supports that.

I'd remove the meter from the board and confirm in isolation but, honestly, it seems like case closed.

They can be repairable, in some cases, if an internal connection has come loose but that's rare enough and very delicate work.


Hopefully you can find a spare part somewhere. Maybe someone on here might even have one?
Decent chance Tascam used the same units across a range of machines.

 

[CoolCat]

okay i've done it now guys! i swapped j202 with j212 and as you said when turning to PGM 1 the meter 2 is moving. and meter 1 is still unresponsive...so that means its the vu meter coil that's broken? its nothing on the pcb..right?

View attachment 153503

Good.. swapping the lines showed you the circuit was not the problem.

fyi...Each connector/signal goes into two separate circuits per the schematic you posted. The signal comes in and splits to
1. Transistor circuit is Overload LED
2. the 901 chip circuit feeds the VU Meter.

Meter 1 has two separate circuits and Meter 2 has separate two circuits. TASCAM decided to put them both on one PCB...

Swapping the connectors showed the VU is the issue because the good meter worked on both u901 VU meter circuits (which means the chip 901 is working and the initial Resistor thought to be bad is fine.) If the circuit was bad the good meter 2 wouldn't have worked on either.

Had Tascam not combined two into one PCB, it might be easier to swap a VU meter.
On an ART MPA or VLA this would be good news because VU meters are easily obtainable, cheap, but not so with this M216...can you remove the VU Meter from the PCB? or is this soldered and attached? anyway probably doesn't matter....you will need to replace the entire unit both meters and PCB, or can maybe just replace the VU meter (if you can find one.)

trouble shooting the VU meter now... is it stuck? doesn't seem to be because you made it move.
can it be repaired? I've never done this....usually replace it, imo.
its a pretty common failure but in this situation Im not so sure your meter is going to be easy to find. ART MPA/VLA or a ISA One, and many others... VU meter fails but are easy to find parts.

my 2 cents-
If you are lucky to find a matching meter part, I would recommend buying 2qtyat least (which is 4 meters) because often items like this have failure rates, Life-span and they are all the same age Ill assume, so if one has failed, the other meters are likely to fail too. I see this at work alot on old machines with obsolete parts reaching their end of life.

Its TASCAM's decision to put both meters on the same PCB. Makes it a little more difficult.

Searching for the Meter ...Its a Vintage part it appears. ....good luck.

Tascam M-208 M-216 M-2516 double VU meter 52101458-00: A tested pair of original dual VU meters mounted to the authentic 52101458-00 factory PCB, occasionally stocked by vintage gear specialists like Tascam Ninja.

Exact OEM replacement VU meters for a vintage Tascam M-216 console must be sourced from vintage parts distributors or salvage gear, as new old stock (NOS) factory parts are no longer manufactured. If you are building a custom project or looking for a standard replacement chassis-mount unit instead, modern generic analog VU meters are widely available.

https://www.

tascamninja.com/products/tascam-m-208-m-216-m-2516-double-vu-meter-52101458-00-meter-5296007100

This ones $290 on eBay...

 

[CoolCat]

you know...steenamaroo is right...the swapping connectors wouldn't isolate the circuit from the VU meter, so only confirms incoming signal,

but anyway.... good luck, at least your channels are passing sound...you have to use your ears and not your eyes with the VU meter out.

 

[CoolCat]

If your outputs are all working...and its in a studio (not live- portable),,,,maybe some outboard VU meters?

 

[Steenamaroo]

We're complicating this as only AI can.

Test the VU in your hand for certainty.

I'd also run Sine waves in to both channels and check voltage at the meter connection points, with VUs removed,
just to make sure your VU hasn't died due to a failure elsewhere on the board.

Based on that, buy a replacement VU, or PCB+ VU pair.

Tascam Ninja has both.
Members here in the analog section may have spares. I'd ask.

 

[CoolCat]

checking in....success? or something else....?

yeah could have swapped a meter lead to see if it was VU or circuit.

seems any Tascam M- model used the same VU design....Ninja shop shows sold out though. Maybe they have some in stock not posted?

can a person deep dive and repair the VU meter?

 

[rob aylestone]

You can - the only thing being that they are small, the wires are microthin and soldering to them is precision stuff. I'd have to use magnification as my eyesight is no good for this kind of work. On top of that, some are welded shit - so you need to split the plastic to actually get inside. Years ago - as in early 80s, I'd heat up scalpel blades and use those to melt through the cases of the Sony ones I managed to fix. If you are the sort of person who has patience to fix watches you will be ok - the usual thing is the coil wire breaks. if it's visible, you can shave the enamel off both ends and solder it back. If the break is mid coil - I'd buy a replacement. Look for old broken gear - sometimes you can see things that appear to have the same meters for silly money. A bit of a gamble if they are the same, but worth considering.