Tascam 788, Pushbuttons intermittent, Any way to "clean"

ejm

New member
The title basically says it all.

My faithful Tascam 788 has a couple of buttons that have become intermittent, specifically the TRACK button.

Is there any way to clean or recondition this, or is it on its way out?

Thanks in advance.
 

ejm

New member
Bumping up after a few years.
The buttons are getting worse.

Any ideas on how to recondition these?

If Tascam reissued the 788, or offered a Portastudio with MIDI, I'd be first in line to buy one.
 
Bumping up after a few years.
The buttons are getting worse.

Any ideas on how to recondition these?

If Tascam reissued the 788, or offered a Portastudio with MIDI, I'd be first in line to buy one.


deoxit does it

one to clean
another type to keep them going - called gold but that is just the name nothing to do with real gold

Home - CAIG

https://caig.com/deoxit-d-series/

https://caig.com/deoxit-d-series/
DeoxIT Gold G5S-6 Spray Contact Conditioner and Protectant - 5 oz.

try also ace hardware walmart and amazon

i thought i had links to radio shack selling it to but they disappeared
use google to find vendors if you dont like those choices above
 

ejm

New member
mr average: Thanks for the reply.
A couple of questions.

1) Have you actually done it, or something similar?

2) Did you disassemble the device?
I have not opend up my 788 yet, but have a feeling that the button section is "buried".
To get to it may require a major tear apart, which I am reluctant to do, since I may not get it working again. ;>))

I don't know if they are mechanical, or some kind of "membrane" type (for lack of a better term).

I have turned the internet inside out, and there is nothing on this problem with Tascam products or anything related.

Anybody got any ideas/tips?

What I'm thinking of doing is:
1) Do not disassemble the unit.
2) Lightly spray some contact cleaner/lubricant safe for plastics around the top of the switch/button, hoping that it seeps down inside. Work the switch/button several times.
3) Follow that up with some Caig Deoxit D100. I looked at the Caig website, and this seemed to be the type most applicable.
4) Pray.

Ant better ideas?

Thanks in advance.
 
mr average: Thanks for the reply.
A couple of questions.

1) Have you actually done it, or something similar?

2) Did you disassemble the device?
I have not opend up my 788 yet, but have a feeling that the button section is "buried".
To get to it may require a major tear apart, which I am reluctant to do, since I may not get it working again. ;>))

I don't know if they are mechanical, or some kind of "membrane" type (for lack of a better term).

I have turned the internet inside out, and there is nothing on this problem with Tascam products or anything related.

Anybody got any ideas/tips?

What I'm thinking of doing is:
1) Do not disassemble the unit.
2) Lightly spray some contact cleaner/lubricant safe for plastics around the top of the switch/button, hoping that it seeps down inside. Work the switch/button several times.
3) Follow that up with some Caig Deoxit D100. I looked at the Caig website, and this seemed to be the type most applicable.
4) Pray.

Ant better ideas?

Thanks in advance.


yes
and it worked great
did not have the gold follow up back then but have not needed it before the gear wore out from real old age

i did not have to take apart as i could reach the pots with the nozzle and spray into a hole in the side of the pot
maybe on the other one i pulled the cover off to reach the pots
 

ejm

New member
mr average: "i did not have to take apart as i could reach the pots......."

The pots for the input trims are not the problem.
It's the many "buttons" for track select, send, eq, track cue, record, etc.
 
mr average: "i did not have to take apart as i could reach the pots......."

The pots for the input trims are not the problem.
It's the many "buttons" for track select, send, eq, track cue, record, etc.

then you may have to pull off the case
that should not be a major problem to do
 

ejm

New member
mr average: So did you clean the buttons, or did you clean the four input trim pots?

"then you may have to pull off the case
that should not be a major problem to do"

I saw a video on YT of a guy replacing a switch for the FFW or STOP or REWIND or similar on a 2488.
If the 788 is anything like that, IMO it IS a major thing to do.

Also: ".....before the gear wore out from real old age"
What gear?
This is a digital recorder/portastudio.
 
mr average: So did you clean the buttons, or did you clean the four input trim pots?

"then you may have to pull off the case
that should not be a major problem to do"

I saw a video on YT of a guy replacing a switch for the FFW or STOP or REWIND or similar on a 2488.
If the 788 is anything like that, IMO it IS a major thing to do.

Also: ".....before the gear wore out from real old age"
What gear?
This is a digital recorder/portastudio.

on my devices only the pots were a problem
so that is all i cleaned
 
Tactile switches are cheap and they do fail and get dirty. These are not a candidate for Deoxit as it does not fix everything. The correct way to address this is to take note of the size and lead types of the switch and then go looking on the Mouser site or the Digi-Key site for compatible switches. I have a couple of hundred in stock of different ones- there are in line lead switches and then 4 leg switches. When you replace them and I did that as far as back in the 80's at Teac the deck works much better. New fresh tactile switches are not that hard to replace. Take note of the problem ones and change away. This is the way a professional does it. I have a Teac V900X that would eject very intermittently. many times it would ignore you. This leads to higher pressure and damage to the keyboard.
Once I put in a row of fresh tact switches the eject seemed to anticipate my command and the eject opened very easy like it was suppose to.
Spraying a chemical in a small switch requires that you get to that switch and if you are that close then why not just change it out? The spray will not last long anyway a new switch will.
 

70sretroguy

New member
Bumping up after a few years.
The buttons are getting worse.

Any ideas on how to recondition these?

If Tascam reissued the 788, or offered a Portastudio with MIDI, I'd be first in line to buy one.

Sorry for the late response, this is a common problem with these machines given their age. The 788 can be opened up from the rear. Pull off fader/pot knobs. lay face down on a padded bench and remove screws from around the edge. Two more screws need to come out from the centre, you can work this out by trying and replacing one at a time and gently lifting. Once unscrewed the first PCB folds out like a rigid book page. A protective plastic sheet, central chassis support and a shiny metal plate (heat sink?) also unscrew easily. However the second PCB is not so easy to lift out due to two very short ribbon connectors on the screen and a short cable on the rotary dial. The ribbon connectors are vulnerable to damage and the other cable needs to be soldered, so this is not a job for a novice.

However, the good news is, it is possible to fix this issue from the front, no need to open it up. I've done this myself a few times with LPS contact lubricant. Costs more than most contact cleaner, but does not damage components and doesn't need to be repeated. Disconnect from the mains and gently wedge the faulty switch up or down in it's square hole with a small flat head driver, whittled matchstick or similar object. Aim the applicator tube into the gap and one good squirt leaves a good splash of fluid in the crevice and around the button edges. Work the switch steadily about fifty times, this should help pump the fluid into the actual contact surfaces. Leave for 24 hours to dry out thoroughly, it smells weird but don't be tempted to put it outside as this will cause humidity issues.

I've done this on four switches so far without any problems. They work like new again, and I've not had to repeat the process. Obviously it's preferable to dismantle and completely clean / replace switches, but this is a practical, easy fix which will keep your 788 going for a few more years. I am currently nursing along two 788s and continue to find them very user friendly practical tools with a modest physical and financial footprint.
 
I have cleaned tactile switches in the past and they do not last as long as new ones. If you want a full life out of them rather than a chemical repair of a short time then that is up to you but professionally I change them out and this I have done for a long time already.
 

ejm

New member
70sretroguy: Thanks for the useful info from someone who has actually dealt with the 788 and this problem.

Question: Do you have a SPECIFIC part number of the cleaner that you used?
I looked on the internet and found a web site for Motion Industries.
They had around 90 different types of LPS electrical cleaners.
I'm sure that most of them would work, but a specific part number is nice to know.
And......from my experience dealing with electrical contact cleaners, maybe the most important criteria is that whatever you use, it should say SAFE FOR PLASTICS.

FYI, in the interim, as a last resort, I also tried what you did a while back.
I first tried using some Deoxit D100.
Long story short, I have not had any luck with any of the Deoxit products.
I then tried some electrical contact cleaner doing basically what you did.
Protect the area around the switch on the top of the 788.
Use the little red tube that they all come with, flatten out the end if necessary, and spray a little into the gap(s) around the switch.
Work it a few times, wait a few minutes before trying.
It's been a few months now, and the 3-4 switches that were iffy still work.
Fingers crossed.

SkywaveTDR: Have you actually repaired any of these 788 pushbutton switches?
If so, did you actually replace the switches?
If so, did you order the replacements from somewhere?
If so, what part number did you order?
 
When you come back and have the same problem as when you started down the road a Teac Technician told you what to do- best to follow the professionals as they deal with this all the time and have the correct method for a final fix. I have replaced tactile switches on a lot of equipment like 688 and488 as well as regular cassette decks- they all work after that. I am sure the spray method would not work with my 6 month warranty. Of course a guy who warrantees the deck to the door will be happy to charge you again as that what they local shops do plus the deposit.
 

ejm

New member
SkywaveTDR: Have you actually repaired any of these 788 pushbutton switches?
If so, did you actually replace the switches?
If so, did you order the replacements from somewhere?
If so, what part number did you order?
 
To answer the actual question NO I have never had a 788 in my shop. In fact a 688 just came in. However, you are talking about a part called a tactile switch that is used in decks from the V900X to the Porta Studios and just about anything else- even my garage door remote has a tact switch in it. Now there are many different kinds- maybe 30 of them. In my shop I have to only deal with 3 or 4 models of switches- There are the axial switches that have only two pin on them- that is why I call then axial. They actually have three pins but the third is a ground pin and can be cut off if not needed. There are the 4 pin switches. There are tall actuator and smaller actuator types. People are always asking me for a part number or to be handed the part on a golden platter- the service business does not work that way. When I pull out a tact switch I go over to a drawer of many kinds that I have and match it up size and pin wise. In almost all cases this is the answer- One switch I have is called the P8010S-ND which came from Digikey.
What you need to do is take out a switch, measure with a caliper and go looking for a present day switch that will fit that size and terminal type- this is what I do. Some switches may not be made anymore and this is what I am finding out which causes me to order larger quantity right now as I am likely to be fixing these for another 10 years and No I do not spray chemicals at them as that is a lazy and wrong way to deal with them.
The issue is this- I have a 6 month warranty and if I do not want to have to work on the machine a second or third time, I have to fix it the right way the first time- the customers come to like that as they don't have to drag the unit in time and again-So spraying a switch is the hack shop way and also shows laziness. Change the switch!
 
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