Kenwood KX-W4040 cassette deck service manual or info needed

[Jimmy Electron]

Hi all.

 Does anyone have access to either one of the Kenwood KX W4040's itself, or the service manual?

 I have a tape deck here which is stuck in standby and has Q78 missing. The only .pdf I can find online is $25 which is out of my price range.

 Any help would be greatly appreciated.

[Jimmy Electron]

 
 This thing has been sitting around for ages and one way or another it has to go.

 It's probably reasonable to give this thread a week and if nothing evolves then I'll scrap it for the components.

 If I'm honest, it doesn't seem to me that the missing transistor is the reason that the unit doesn't turn on, however without the schematic, I'm not really sure where to start looking. The power supply section has one +12v and one +15v 78xx series regulators which are both fine. I haven't really tested the multitude of electrolytics nor semiconductors. There is one relay which appears to be activated from tape deck A and not likely to turn on the whole unit.
 Working back from the power button, one side leads to I/O Port, pin 14 on the 64 pin main microprocessor IC, a Kenwood branded M50946-109SP, although which pin it passes through after that is another question? The other side of the power button goes back to pin 56 which is a high-voltage I/O Port.
 As it's Sunday, I'll have another look and follow up here if anything else comes to light.
 

[elantric]

https://www.ebay.com/itm/203917543329

[Jimmy Electron]

 Thanks for that, only I am currently in Brazil and with the communist government there is 100% import tax not only on the item but then also the postage, hence the need for a .pdf

[David_AVD]

Is the Kenwood KX-W4050 model similar enough?

[Jimmy Electron]

Is the Kenwood KX-W4050 model similar enough?

 Hi David,
 unfortunately not, but many thanks for the suggestion.

 I had been looking through the 4050 and 4060 manuals in that hope, but there are many differences, not least that the main processor chip is of a completely different type, being 64 pin as opposed to the 80 pin in 5060 and 6060..

[Jimmy Electron]

Last post for today.

 Probing deeper into the circuitry, one side of the relay coil in fact goes direct to the centre pin of Q78, the missing transistor, so 100% this transistor needs to be identified in order to be replaced.
 The other side of the coil is the VCC supply rail running at just under 15v and connects to other components such as an LA3246 stereo preamplifier for double cassette players.


 

[coromonadalix]

check this one for similarities ?
https://elektrotanya.com/kenwood_kx-w4080_kx-w6080.pdf/download.html

they loved to use the same decks upon many models

[David_AVD]

Well, you can work out if Q78 is NPN or PNP and the pinout. The footprint will give you an idea of the original package type and probable current rating. Pick something with a 50V rating and go from there?

[jonovid]

on us.archive.org  is this pdf link
https://ia802309.us.archive.org/16/items/manual_KXW4050_SM_KENWOOD/KXW4050_SM_KENWOOD.pdf