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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 27th Sep 2018, 1:05 pm   #1
NorfolkDaveUK
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Default N4510 help needed

So I`m back to this again . I`m trying to follow the setup procedure but I`m struggling right from the off .

I`m inputting 333Hz @ 330mv and at the monitor I should be able to adjust it down to 1v however I can`t get it lower than 2.5v rms any ideas what might be causing this ? I suspect this is why the input on this thing is uber hot the scope is also not showing the 333hz coming out its showing 50hz coming out .
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Old 27th Sep 2018, 1:18 pm   #2
ms660
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Default Re: N4510 help needed

The 50Hz output sounds like something might be floating?

I would follow the signal through with the 'scope from the input from your generator.

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Old 27th Sep 2018, 1:21 pm   #3
NorfolkDaveUK
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Default Re: N4510 help needed

OK thanks I`ll see if I can do that cheers. Just printing off the manual
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Old 28th Sep 2018, 3:03 pm   #4
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Default Re: N4510 help needed

So I`ve been at this all morning trying to figure out why I can get these values to make any sense , the only way I can configure this to the spec the manual is asking for is to use peak to peak values . How do you determine if you are supposed to use peak , RMS or peak to peak ?

Thanks
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Old 28th Sep 2018, 4:31 pm   #5
ms660
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Default Re: N4510 help needed

AC voltages are usually quoted as RMS unless otherwise stated.

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Old 28th Sep 2018, 4:59 pm   #6
NorfolkDaveUK
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Default Re: N4510 help needed

Thats what I thought , its stating use a milivoltmeter so it would lead to RMS being correct, however if i use rms for both input and output , I cannot get the results I should at all . Something very bizarre is going on with this deck for sure . The transistors on the playback cards have been replaced for BC550`s so they should all be good . The caps have been replace also , using the test point inputs there is nothing in the way really . A real head scratcher for sure .

I`m putting 333 Hz in @ 330mV RMS , and I`m getting out a MAX of 750mV RMS at the monitor output with the VR`s fully wound open but its calling for 1v

I sorted out the 50hz thing btw , the ground lead for the function gen wasn`t quite connecting .

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Old 28th Sep 2018, 5:18 pm   #7
NorfolkDaveUK
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Default Re: N4510 help needed

If we have a look at the schematic , there`s nothing really to stop the signal coming thought as it should . The signal is getting lost somewhere between pin one of the playback card and the monitor output because the signal coming out of pin 1 on the playback card can be adjusted to 1v RMS no problem . One of the resistors gone high maybe ? Its both sides though .
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Old 28th Sep 2018, 5:51 pm   #8
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Default Re: N4510 help needed

I notice the signal goes through several switches. These will be part of the slide switches on the main PCB and I have had a lot of problems with them in the N4510 (and N4450).

It's best to take them apart and clean them. Basicaly you remove the operating lever (unscrew the pivot screw) and then take off the clip that holds the pin through the coupling block. Remove the pin and take off the block

The slider then comes out. One end (I forget which) is thinner than the other. It must be removed with the thin end coming out last (i.e. pull on the thick end) and fitted thin end first (so you push on the thick end). Also don't turn the slider over and don't swap them between switches. Clean the slider contacts with propan-2-ol (IPA) and then spray that into the switch, fit the slider and work it back and forth. Remove the slider and clean it again. Repeat a couple of times. Then put the whole lot back together.
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Old 28th Sep 2018, 7:14 pm   #9
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Default Re: N4510 help needed

Thanks Tony . I`ve done it with a couple of them . It also goes via the relay so I think I`ll have that apart and clean that too .

Thanks bud.
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Old 28th Sep 2018, 7:19 pm   #10
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Default Re: N4510 help needed

At least on mine the relay is plugged in. After removing it you can unclip the cover then remove the tension spring on the top and carefully extract the moving contact assembly. Clean all the contact faces with propan-2-ol on a cotton bud.

There are some photos that might be useful in my flickr account (tony_duell). Look in both the N4510 and N4450 albums, the 2 machines are somewhat smilar so I didn't photograph stuff on one machine if I'd done it for the other.
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Old 28th Sep 2018, 8:17 pm   #11
NorfolkDaveUK
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Default Re: N4510 help needed

Mate these photos are brill . I`ve been looking for photos of the boards , these are just great thanks !
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Old 29th Sep 2018, 1:06 pm   #12
NorfolkDaveUK
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Default Re: N4510 help needed

I`m still getting no-where with this . If I switch the output to 1-3 or 2- 4 then there is plenty of voltage to allow me to set what i need but in stereo , it drops like a stone . I`ve cleaned all the switches and relay relentlessly and it still doesn`t want to play fair with me i`m trying to figure out which pin is which on the stereo switch but its such a yucky board I`m struggling a bit with that too ....sigh.
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Old 29th Sep 2018, 5:42 pm   #13
NorfolkDaveUK
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Default Re: N4510 help needed

I`ll continue this when I get the scope upgrade I`ve just ordered . I can`t trust the one I`m using (Chinese USB scope) , so I`ll be back again at some point next week with this one
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Old 29th Sep 2018, 6:08 pm   #14
TonyDuell
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Default Re: N4510 help needed

If it works in some switch positions but not others it's a fair bet the switch is the problem. Do check that the slider has not been turned over, that can cause some very odd problems.

I found you could check the switches with nothing more than a continuity tester, just make sure that the signal goes from a pin on the module to the switch, then out of the switch to the next switch and so on.
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Old 29th Sep 2018, 6:35 pm   #15
NorfolkDaveUK
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Default Re: N4510 help needed

I`ve noticed on one of the switches there is some soldering going on . I`ll take a pic in a few ...looks like its been "bodged" somehow.
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Old 29th Sep 2018, 7:18 pm   #16
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Default Re: N4510 help needed

Quote:
Originally Posted by TonyDuell View Post
If it works in some switch positions but not others it's a fair bet the switch is the problem. Do check that the slider has not been turned over, that can cause some very odd problems.

I found you could check the switches with nothing more than a continuity tester, just make sure that the signal goes from a pin on the module to the switch, then out of the switch to the next switch and so on.
Yes of course you can use a continuity tester but a signal tracer is very useful when checking the switches on these and other similar machines. I worked on a good many of these when at Philips but of course spares were not a problem then. I built a simple signal tracer and found it much quicker than using a testmeter.
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Old 29th Sep 2018, 8:10 pm   #17
NorfolkDaveUK
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Default Re: N4510 help needed

I use a signal tracer i built from an set of pc speakers . Much more useful than my scope in some situations .
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Old 10th Oct 2018, 7:53 pm   #18
NorfolkDaveUK
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Default Re: N4510 help needed

OK so I`m going to dig this one up again , the tandberg is on hold while I sort this one out . So I now have 2 of these philips 4510`s , and so I can do some card swapping and find out exactly whats what with this . So , so far I have takes the input , before tape and record cards out of the older machine and put it in the new one (new meaning the one thats just arrived here ) , here`s the results ,

Both the input and both the before tape cards are good in the older machine , one of the record cards in the older machine is dead and the other is fine . So first thing I need to do is repair that . So thats what I`m going to do . Once I have a working set of cards , I can THEN get on and find any more faults that come up once I know the cards arent this issue .

Now , the NEW machine , I can`t hear the input at all (on both "Before " and "after" tape ) , I can see it on the vu`s , and I can record it and play it back no problem at all , I THINK this is normal on these and you have to listen to the monitor output to hear it is that correct ? I haven`t tried listening to the monitor output yet I`m more worried about getting the other one working .

Thanks my kindly techie buddies , as always .
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Old 10th Oct 2018, 10:49 pm   #19
NorfolkDaveUK
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Default Re: N4510 help needed

Ok so with the amp connected to monitor , and the source (my phone ) connected to tape in/out input and the cards out of the new machine in the old machine we have lift off . So fix that broken record card and I`ll have 2 of these in working order . Sweet . Thank the lord for that . lol .
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Old 11th Oct 2018, 1:00 am   #20
NorfolkDaveUK
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Default Re: N4510 help needed

Gosh darn it , I think the record head one one of the decks is gone . It records however it`s muddy as heck , and on close inspection they look like the pic ....it never rains but it pours huh ... I`ve tried calibrating it but its still really muddy so I guess I`ll have to look for a record head for it . I`m reluctant to pull the other one and try it as the other one works great so I`ll be leaving that be . I`ll swap the control boards out tomorrow and see how the amps sound but i`m pretty sure its that dodgy looking head .
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