Bush KCS-317 cassette recorder speed adjustment
2024-Apr-17, Wednesday 10:30 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
chebeThe Bush KCS-317 cassette recorder/player is a recent, budget, device for playing, and recording, audio cassette tapes. I picked it up during lockdown when I wanted to digitise old tapes I'd found, but discovered that my existing players were no longer functional. If I recall correctly I had exactly two options; a portable player, or this one, which I chose for the mains power plug. It has a bunch of other features, like playing from usb sticks, none of which I'd needed. But the sound quality was never good.
I recently fell down the Steve's Electronic Repair Shop rabbit-hole, and the 'Cassette Tape Player. How it works and how to repair.' video in particular emboldened me to sort out that player. So I found a speed calibration test tape which has 15mins of 3,000Hz sine wave (actually 3,010-3,020Hz), and instructions on how to use it. The tape showed the player to be running fast, and as if I needed more encouragement, the buttons, the big chunky physical plastic buttons got stuck in play. It had to be opened up.
(I couldn't find any photos, or manuals, online for this player, so I'm including more than is necessary here in case anyone ever needs them.)
There are five screws in the base of the player, readily marked. But they are bigger than the ones I usually encounter doing electronics stuff. After removing those screws, put the player down again, press 'Eject', and the top face just slides off. The plastic buttons are likely to scatter. But this at least enabled me to reset the button levers. The plastic parts had bad flash from the moulding process, which I believe is what caused the buttons to stick. So I trimmed the excess off.
The play head is labelled 'YC0G16 1F25', and looks to be a mono head. Mono certainly requires me to re-evaluate my expectations.
And then there's all the reels, idlers, a mixture of metal and plastic mechanism.
The underside of the mechanism has the belts. (This is a new player, so I didn't expect any problems with the belts.)
Under the mechanism is the PCB, and other parts. The point of that screw (that seems to exist as a heat sink?) is right up against that capacitor and makes me feel all kinds of uncomfortable.
The bottom of the PCB is nice and boring, besides the coppery sheet it is sandwiched with.
Problem is, I couldn't find the speed adjustment screw/trimmer anywhere on the PCB. Eventually I noticed the hole in the top of my motor (EG-530AD-6F), and cracked it open. It just led to another hole. But when I put a philips head screwdriver (a really small one, like for glasses or mobile phone repair) down into it there was purchase. Having identified only one candidate I put everything back together, except for the top case.
With the top case removed I could plug in the player, play the speed test tape, and ever so gently adjust the motor speed with immediate feedback. It is a horrible sound, but a very effective test. After I got the frequency to between 3,010-3,020Hz I closed it back up properly, and tested it with a well known tape. The in-built speaker is not good. The in-built microphone is not good. Considering it has a mono tape head, and doesn't have Dolby Noise Reduction, there is a limit to what I can expect from this player. But with the correct speed setting it sounds okay, on headphones at least.
I recently fell down the Steve's Electronic Repair Shop rabbit-hole, and the 'Cassette Tape Player. How it works and how to repair.' video in particular emboldened me to sort out that player. So I found a speed calibration test tape which has 15mins of 3,000Hz sine wave (actually 3,010-3,020Hz), and instructions on how to use it. The tape showed the player to be running fast, and as if I needed more encouragement, the buttons, the big chunky physical plastic buttons got stuck in play. It had to be opened up.
(I couldn't find any photos, or manuals, online for this player, so I'm including more than is necessary here in case anyone ever needs them.)
There are five screws in the base of the player, readily marked. But they are bigger than the ones I usually encounter doing electronics stuff. After removing those screws, put the player down again, press 'Eject', and the top face just slides off. The plastic buttons are likely to scatter. But this at least enabled me to reset the button levers. The plastic parts had bad flash from the moulding process, which I believe is what caused the buttons to stick. So I trimmed the excess off.
Heads, pinch roller, and capstan
Photo by chebe
The play head is labelled 'YC0G16 1F25', and looks to be a mono head. Mono certainly requires me to re-evaluate my expectations.
Close up of the play head
Photo by chebe
And then there's all the reels, idlers, a mixture of metal and plastic mechanism.
Reels, idlers, top of mechanism
Photo by chebe
The underside of the mechanism has the belts. (This is a new player, so I didn't expect any problems with the belts.)
Belts, bottom of mechanism
Photo by chebe
Under the mechanism is the PCB, and other parts. The point of that screw (that seems to exist as a heat sink?) is right up against that capacitor and makes me feel all kinds of uncomfortable.
Top of PCB
Photo by chebe
The bottom of the PCB is nice and boring, besides the coppery sheet it is sandwiched with.
Bottom of PCB
Photo by chebe
Problem is, I couldn't find the speed adjustment screw/trimmer anywhere on the PCB. Eventually I noticed the hole in the top of my motor (EG-530AD-6F), and cracked it open. It just led to another hole. But when I put a philips head screwdriver (a really small one, like for glasses or mobile phone repair) down into it there was purchase. Having identified only one candidate I put everything back together, except for the top case.
Motor casing opened up
Photo by chebe
With the top case removed I could plug in the player, play the speed test tape, and ever so gently adjust the motor speed with immediate feedback. It is a horrible sound, but a very effective test. After I got the frequency to between 3,010-3,020Hz I closed it back up properly, and tested it with a well known tape. The in-built speaker is not good. The in-built microphone is not good. Considering it has a mono tape head, and doesn't have Dolby Noise Reduction, there is a limit to what I can expect from this player. But with the correct speed setting it sounds okay, on headphones at least.
Adjusting the motor speed
Photo by chebe
