National Panasonic RX-5410 double restoration

[crazygamer]

Hello,

As my associate collector took D8444 off my hands, he brought me 2 of those mono boxes. They look very nice outside, but both need a good DeoXit cleaning, inner cleaning from goo and debris, new belts etc.

I took them apart the very same day, everything looked quite nice this far,, some deoxit here and there, new belt and lubrification, but when i assembled it all together just like i disassembled it but in reverse order, it didn´t do anything at all. Total zero. Cassette spindle spinned very slowly, no radio at all, no nothing, i guess something´s wrong with them but i don´t know what is wrong. I guess it´s a case of those shielding things, those carton things that are fixed with screws. I also took apart the second one, before it worked well, but deoxit was needed, did some deoxit tricks, cleaned it, also assembled and again, no action whatsoever. I quite lost my mind about it and it has been my biggest disappointment so far. :'-( How come it just doesn´t turn on.
As it´s holidays, i won´t take it apart again yet, but i promise i´ll get back to them at some point. All plugs are put back just the way it were, but no action at all. Please, help me !

 

[toshik]

Most likely missing the ground or power someplace - you did not put something back correct way.

 

[MyOhMy]

I had the same problem a few months ago with a Hitachi TRK-8130, there wasn't a sign of like. I rechecked all the connections and found that I'd put two single-wire connectors, located side-by-side, in the incorrect sockets. Just two tiny wires = Death By Negligence. All was well after swapping the wires around.

 

[crazygamer]

I guess i have to take a look of those points marked on the photo or what ?

 

[MyOhMy]

Re-check every connection to make sure they are correct and sound.

Look closely at the connections on the printed board(s) as they sometimes have one or two letters printed on them near to the connecting points: R, BL, BK, OR etc. (Red, Blue, Black, Orange).

This also helps identify which pairs/groups of wires go where. For instance, a Blue & Yellow pair of entwined wires should not be placed in adjacent BL & BK connectors (in my limited experience), look for adjacent BL & Y connectors in this case.

It's at times like this that a Service Manual comes in handy!

 

[MyOhMy]

When I opened the case on my first Hitachi TRK-8130 two wires became unplugged without me realising until I put the box back together again. When closing this particular case, the two sides have to be almost together before the last two connectors can be refitted.

This is where they are fitted, note the lettering by each
connector: (BLK)=Black, (GRN)=Green.


Now, every time I work on a box I take many, many pictures from every angle - just in case I need them. Sometimes, connectors may look similar so I've marked some and made the same mark on the board, with others a photograph with a pointer to help.


All these are simple precautions that minimise the risk of mistakes. I take many more photo's than I'd ever use but that's just me being cautious. Hope this helps.

 

[crazygamer]

Alright, will do, it didn´t have those letters marked on at all, i thought it´s all related to this paper sheet and clip thingies but i actually know what their purpose are. i took those top pictures before reassembly and i took a look of this photo so i could put it back together, but i guess i need a better camera next time as my old camera is absolutely no use at all.

This Panny i´m working on is way different than this Hitachi, i´ve familiar with those BLK YEL GRN wires and plugs and i´ve worked on them before without flaws, but this time i ran out of luck. Ah well, i hope everything is still alright with this machine. After holidays i´ll take them apart for good and look what i can do about it. Thanks for help, but is there anything particular about this machine i have to overlook again ?

 

[BoomboxLover48]

Clean the long record switch with Deoxit! Move it back and forth 30 times min.

I've had this no power problem and everything came back to life!

Try that and see...

Next look for any bad solder joints at the back of the board. Slowly move components on the board with a small Q tip or tooth pick without shorting connections.

Is it getting power on the rails?

Did you use batteries and check?

 

[crazygamer]

Clean the long record switch with Deoxit! Move it back and forth 30 times min.

I've had this no power problem and everything came back to life!

Try that and see...

Next look for any bad solder joints at the back of the board. Slowly move components on the board with a small Q tip or tooth pick without shorting connections.

Is it getting power on the rails?

Did you use batteries and check?

I mean, before disassembly it kinda worked, but after assembling it all back together it didn´t. No visible damages, all solder works were fine, but i´ll take a look for sure when i open it up again.

 

[jimmyjimmy19702010]

The same exact issue with 2 units leads me to believe it is a reassembly issue.

 

[Ken]

The same exact issue with 2 units leads me to believe it is a reassembly issue.

 

[BoomboxLover48]

The same exact issue with 2 units leads me to believe it is a reassembly issue.

Good thought! There is a good chance!


Check if the PC board is in some sort of strain. I've seen hairline cracks causing issues.

Don't put it all together until you make sure everything works.

Also check the functionality in every step of the way when you to put it together.

Make it a point to take pictures on what you are disconnecting and make a note of it also. Pics taken on each step of dis-assembly helps a lot.

5410 is a box I am dreaming for years to acquire!

 

[crazygamer]

I also guess it´s not something serious. PC board is alright,this thing is bombproof i tell you I´ll keep those suggestions all in mind in further restorations, big thanks ! I´ll wait until i get a new camera so i can make way better pictures. Old camera is quite miserable and out-of-date in many ways But what about those grounds, what happens when they´re not connected to somewhere, there are some wires with screws in the ends and they also connect to somewhere. And someone tell me the purpose of those paper sheet things ? Is it some kind of RF shielding and does it matter if it´s there or not ?

 

[jimmyjimmy19702010]

Always mark those white connectors (the ones that all look the same) before you pull them. Some may carry audio signals but others may carry power. If you get them around the wrong way, you can end up feeding power to an amp signal input/output for example - this could blow out the amp etc.

If the unit won't power up, you could be feeding power to the wrong circuit.

As both units have the same 'fault', you may have made the same reassembly error with both units.

Hopefully it's something simple. Good luck.

James....
View attachment 24230

 

[MyOhMy]

..................And someone tell me the purpose of those paper sheet things ? Is it some kind of RF shielding and does it matter if it´s there or not ?

At a guess I'd suggest the large piece of paper/card is there to prevent wires/'something' from making contact with that part of the board.
The smaller pieces of paper/card, I'd suggest, look like they are there to restrict the movement of wires/keep wires in specific places therefore preventing them from interfering with other elements of the board. Just a guess but they look like they're providing a useful service and can easily be replaced if needed.

 

[crazygamer]

Took it apart, i reassembled everything just like on the photo before disassemblying this piece last time but i guess this just didn´t work out. I took it all apart again and i´ll see what happens next.

 

[crazygamer]

It even has small wire connection plan inside and according to it i´ve plugged all wires in just like shown on plan, but i don´t get it why it still hums when turned on, no action from speakers at all.

 

[crazygamer]

So far i´ve assembled it back together just like shown on photo and plan, but when turning it on it just hums, nothing else.

 

[BoomboxLover48]

Hum could come from bad filter capacitors in the power supply. Use batteries instead of AC cord and see how that goes. Check ground connectors if any are loose.

 

[crazygamer]

Hum could come from bad filter capacitors in the power supply. Use batteries instead of AC cord and see how that goes. Check ground connectors if any are loose.

I also guessed the same, but i´ll give it back to it´s owner who will take it to repair man who will fix that and return it to the former glory.