Do I need a tech to fix a dodgy input jack?

Legionreturns

My little H&K Tubemeister 5, which I use for my youth club stuff, has an input jack problem. I believe it was caused by one of the kids tripping over a cable. It doesn't accept the jack all the way in now, I believe the spring is bent. Should be relatively simple to fix, right? 

I've never opened up an amp before, and don't own a soldering iron. 

Pics for reference:

strtdv

I would suspect everything is soldered directly onto the board on an amp like that, so if the jack needs changed you may want to get someone to do the work for you.
However, some of these jacks are open units in which case you should be able to bend it back quite easily, just don't touch other stuff in the amp and don't apply excessive pressure if it's board mounted (a jack is easier to change than a cracked board)

Legionreturns

Thanks @strtdv ; that's useful info. Daft question, but with it powered off could I potentially bend it back with a little screw driver without opening it up? 

Roland

Probably not, and it might not bend the way you want it to. You’re better off opening the case, and seeing how it’s bent out of position. Then ask is why it’s bent, and whether simply bending it back will solve the problem for more than a few days.

ICBM

Could there be the tip of a jack plug broken off in there? It looks like there might be in the first pic. This is quite common with cheap nasty far-east-made plugs.

You will need to open the amp up anyway - it there is the tip of a plug in there you'll need to lift the contacts with a small screwdriver and let it fall out. If the contacts are badly bent you'll need to replace the socket, which is probably a job for a tech since it will be soldered to the PCB, and getting at the pins may be even more difficult - quite often the whole PCB has to come out.

If it is the tip of a plug, you *may* be able to superglue something like a toothpick into the hole in the middle and pull it out, but it's fairly unlikely I think.

DJH83004

If it is anything like its bigger brothers, I'm afraid its a pig of a job to get the main board out to access the track side to de-solder the socket. If this is the case then definitely off to the tech I'm afraid .   

ICBM

DJH83004 said:

If it is anything like its bigger brothers, I'm afraid its a pig of a job to get the main board out to access the track side to de-solder the socket. If this is the case then definitely off to the tech I'm afraid .   

In that case I'd be inclined to do it the 'guerilla' way - cut away the jack from above, then solder flying leads to the stumps of the pins, and fit a new panel-mounted jack upside down above it. This also makes later re-replacement of the jack when it gets broken again (almost inevitable in this kind of usage situation) a five-minute job...

Legionreturns

Oh bugger! I was hoping it was a simple fix! 

Anyone recommend someone near Huddersfield? 

Thanks all for the advice. I'm going this doesn't make it a write off, or the child in question is getting a bill. They were being a dick at the time

DJH83004

I wouldn't get too disheartened, doing it the way IC suggests makes perfect sense, and your local amp tech will be able to do that well within the initial diagnosis period / charge.

drwiddly

Legionreturns said:

Oh bugger! I was hoping it was a simple fix! 

Anyone recommend someone near Huddersfield?

Not that close but, if you need an amp fixing, Dave's your man!
http://www.ajeweb.co.uk/ra/

Legionreturns

DJH83004 said:

I wouldn't get too disheartened, doing it the way IC suggests makes perfect sense, and your local amp tech will be able to do that well within the initial diagnosis period / charge.

I was hoping nobody carried that suggestion on...I understood about two words of it, and none of the technical ones!

ICBM

Legionreturns said:

I was hoping nobody carried that suggestion on...I understood about two words of it, and none of the technical ones!

Basically it means that rather than doing it the proper way and removing the PCB so you can get at the solder joints and replacing the jack exactly as it's done originally, you short-cut the process by destroying the jack in situ and then 'bodging' a replacement. This not only has the advantage that re-doing the bodge later is much easier, it's also a slightly better way of doing it in the first place since the jack then doesn't transfer any force to the board if the cable is tugged.

I used to not approve of this sort of 'bodge', but experience over the years - especially with school and rehearsal-room amps - has proved that it's actually the more sensible way of doing it in many cases.

But *first*, before you do anything else, check that there isn't the broken tip of a plug in there. It looks like there might be, and the distance the plug now goes in is perfectly consistent with that. If so, you don't need to replace the jack at all.

Legionreturns

ICBM said:

Legionreturns said:

I was hoping nobody carried that suggestion on...I understood about two words of it, and none of the technical ones!

Basically it means that rather than doing it the proper way and removing the PCB so you can get at the solder joints and replacing the jack exactly as it's done originally, you short-cut the process by destroying the jack in situ and then 'bodging' a replacement. This not only has the advantage that re-doing the bodge later is much easier, it's also a slightly better way of doing it in the first place since the jack then doesn't transfer any force to the board if the cable is tugged.

I used to not approve of this sort of 'bodge', but experience over the years - especially with school and rehearsal-room amps - has proved that it's actually the more sensible way of doing it in many cases.

But *first*, before you do anything else, check that there isn't the broken tip of a plug in there. It looks like there might be, and the distance the plug now goes in is perfectly consistent with that. If so, you don't need to replace the jack at all.

Thanks for that explanation. 

As for the plug, the one that got tripped over snapped at the base of the plug but came out whole. I don't know how anything else could have got in there though. I'll have a closer look of I can get the back off without blowing myself up. 

ICBM

Legionreturns said:

As for the plug, the one that got tripped over snapped at the base of the plug but came out whole. I don't know how anything else could have got in there though. I'll have a closer look of I can get the back off without blowing myself up. 

If it came out whole that's not it then. That's not good, since from the pic it looks like the socket must be damaged.

You won't blow yourself up if you leave the amp turned off for a sensible amount of time before you open it - I assume it hasn't actually been turned on since it happened anyway - and make sure it isn't plugged in. With no standby switch, it's difficult for the caps to retain much charge when the amp is turned off.

Legionreturns

Because I am blonde, it's taken me a while to notice. It was used and working fine yesterday until I started getting a loose connection. Or was only then that I realised the jack wasn't fully inserted, and indeed wouldn't go in further. 

Legionreturns

With apologies to @ICBM ; it did indeed turn out to be a Jack tip. Looks like I'll be using all my own cables from now on, that's two belonging to the youth club that have broken and they're clearly a bit cheap and nasty! 

Fixed it myself, with judicious use of a cocktail stick and an olive fork (being middle class has advantages you'd never realise until this happens!) 

Thanks for your help folks, all tested and working fine.