Tascam 246 bent circuit board, ever see this before?

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cjacek

cjacek

Analogue Enthusiast
Hi guys,
I'm going through a Tascam 246 that I bought locally some time ago, testing functions, cleaning up melted rubber etc.. and have found something rather odd. The photos attached below show the "monitor B pcb assembly" being bent at the front end, what looks like that orange oval capacitor pressing on the headphone out jack (which is modular, is only held by metal clips and plugs into the monitor pcb). I'm thinking to remove the clip, loosen up headphone jacks so that bent pcb straightens out but then what? I can't really reinsert the jacks without bending the pcb again, unless I actually bend the capacitor to one side, which actually worries me, haven't done that before. Does anyone see a simple clean solution here or something else I might try?
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Hi,
That is a bit strange.
It does look like the problem just just the disc capacitor catching on the socket housing.
The capacitor wont care if you bend its legs slightly - Just take the pressure off by bending the board more than it already is, very slightly,
then push the capacitor down a little bit so it won't catch any more.

If bending the board doesn't feel like a great idea then, yeah, loosen or remove the socket assembly then bend the cap down slightly.

It doesn't look like anything else is going to catch or cause an issue but, of course, I'm just looking at photos.
Satisfy yourself of that first. (y)
 
Thanks for the advice, good options. I'll probably take option two (cause bending the board a bit more makes me nervous indeed), even though that will mean a bit more work, having to take the top cover off to better access those clips (although that's still fine cause I need to change the pinch roller and idler tires anyway, and it's easier from the top, having done this before). I assume the disc capacitor's legs won't snap off or weaken if I slightly bend it?
 
Fair enough - Never hurts to be cautious.

No, the legs won't snap with one or two gentle bends unless they're already weakened or damaged.
If you wanted to break the legs that way it'd probably take a dozen or more bends back and forth.



Looking at it again the cap seems to be soldered in place at a bit of an angle.
It may be that if it was reflowed and allowed to sit closer to the board it may no longer catch on the socket,
but the first suggestion seems simpler.
 
Looking at the photos a bit closer, it does seem as if the orange cap is soldered in a bit crooked. (As Steen says)

If so, reflowing the solder joint while pushing the cap closer to the board might do the trick and give you clearance.

Now here’s a question. Does it touching the housing actually stop you from inserting the jack?
 
Yeah Daniel I agree with all of the above. It’s okay that the PCB is a little displaced but like you I’d prefer there not be that pressure. I wouldn’t hesitate at all to fold the ceramic cap to one side or the other, and probably wouldn’t worry about the solder joints, but I don’t disagree with the advice to re-flow them. And actually they’ve been under stress all this time too so that probably is a good idea to heat up the iron.
 
RFR: The jack inserts no problem, all works well. Although the crooked orange cap might be difficult to re-solder or re-flow because, looking at it closer, one of the legs (the front one) is sort of folded in half and bent at the base too, likely from pressure on that cap when someone previous to me must have not been too careful (see photo below). My guess is they were trying to do something with the headphone out connector because one of the metal inserts (where the headphones plug into from the front) is missing. I won't touch the solder for now, will just carefully bend the cap a bit to allow clearance, as was suggested and see what happens.

Cory: This might be a little OCD but since caps do heat up when in use, would it be better to bend the orange ceramic cap away from the other caps (up, as seen in photo) rather than down toward the other caps, which seem a little too close or does it matter? I'm now concerned about that one folded leg on that cap. I honestly don't want to tinker with it, other than try to bend the cap to give it clearance but seems this "fold" kind of complicates things.

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cjacek said:
RFR: The jack inserts no problem, all works well. Although the crooked orange cap might be difficult to re-solder or re-flow because, looking at it closer, one of the legs (the front one) is sort of folded in half, likely from pressure on that cap when someone previous to me must have not been too careful (see photo below). My guess is they were trying to do something with the headphone out connector because one of the metal inserts (where the headphones plug into from the front) is missing. I won't touch the solder for now, will just carefully bend the cap a bit to allow clearance, as was suggested and see what happens.

Cory: This might be a little OCD but since caps do heat up when in use, would it be better to bend the orange ceramic cap away from the other caps (up, as seen in photo) rather than down toward the other caps, which seem a little too close or does it matter? I'm now concerned about that one folded leg on that cap. I honestly don't want to tinker with it, other than try to bend the cap to give it clearance but seems this "fold" kind of complicates things.

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Daniel, certain resistors may get warm, I wouldn’t expect that ceramic cap to get warm, and even if it does many electrical components are rated for their service life to operate at 85C, even up to 125C or more…this stuff doesn’t get that hot. Power transistors do but Teac was always good about mounting them to a proper heat sink. I wouldn’t worry in the least about that capacitor’s proximity to other components. The “folded leg” is normal…you can get components with “kinked” or “straight” legs. That cap is a kinked leg cap. The kink sets a maximum insertion through the holes in the PCB. I fold components over all the time when inspecting boards or to give myself clearance to get to another component to inspect or verify values…I bend it over, bend it back…here’s a YouTube Short showing me just now bending components all over the place on one of the input boards out of an Audio Technica ATRMX-64…I’d have to bend them back and forth many times before they’d break. And the legs have a lot of give so there’s minimal stress to the solder joints. This is not true of all components…some, like larger transistors are more stiff. But ceramic disc capacitors, 1/4W resistors, TO-92 packaged transistors, the stuff that’s all over the boards in a 246, no problem.

 
WOW, Cory, thank you!! This makes me a lot LESS nervous now. Information GOLD. Thanks again. :)
 
Yup, +1 to all of that.
It's actually that one leg has become straightened due to the stress, rather than the other becoming bent, or a mix of both.
Either way, I wouldn't hesitate to just bend the cap down slightly for clearance.

Heat is not going to be an issue for it. (y)

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I was attempting to remove the front case and looks like I hit a road block. Now mind you that I had done this before a number of years ago (on another 246 unit). I pulled off all the sliders and control knobs and (from the bottom) removed all the screws as shown in the service manual (copy of the page attached, see 4-3-1 section instructions and diagram / image), 9 tapping screws (A) and 1 long screw (B). I turned the unit upright and proceeded to very carefully pull the plastic case up starting from where the meters are, so that I could then slide it out from the slightly protruding 1/4" connectors up front. Well, the left side was coming off easy but something was holding the right side tight as a door nail (where the right corner / cassette compartment is). I flipped the unit over and checked and re-checked that all the correct screws were taken out. They were. All of them. Flipped the unit upright again and still nothing. That right side / corner is stuck, like I can actually pull the whole right side up just by the plastic trim. Nothing that I see is catching. I checked the heads, they're pulled back down, not catching. Anyone had something like this happen?
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I don’t really know Daniel as I’ve never had a 246, but just to confirm you’re trying to remove the bottom cover or the top?
 
The top cover Cory. It's basically the same procedure as on the 244, just the screws being in slightly different positions. Something is holding tight onto the right side / corner where the two small VU meters are located or, when looking at the 4-3-1 diagram, that upper left corner
 
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So it’s not the two small screws in the cassette bay?
 
I will have to check again to make sure I'm not overlooking something. I also might get one of those tiny inspection cameras with a light to see what's going on in there. I don't think there are any screws in the cassette bay. I know the 464 (and likely the 488) has those but not the 246.
 
I don’t know if this is the problem, Daniel, but do the two screws, the type with two dimples in each head vs slotted or Phillips, that fasten the small panel over the head lock assembly fasten to the chassis or bottom cover or do they just fasten to the top cover?

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I appreciate you hanging in with me Cory :) . Those two screws are not the issue because all they do is affix the head cover. The issue is more in the upper right corner, it's really stuck there, despite all screws being take out. I'll have to carefully re-check everything.
 
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