Hi guys, fairly new to the CPC464 scene and I'm trying to get a CPC464 up and running. All is fine, but I cannot get the tape drive working and was hoping for some pointers please?
Basically when I try to load a tape and press a key the Play button pops back up, or the tape spindles do not turn. I've tried to capture it on video here to see if you guys had seen this issue before and whether it is fixable or if I'm wasting my time.
I've replaced the belt, and also taken another video with the circuit board moved away.
I'm still not able to identify what is causing the issue. Any thoughts?
Hi,
between the erase head (the white one on the left) and the read head (the silver one in the middle) there is a white wedge shaped piece of plastic. This measures the tension on the tape and is what stops the tape when it gets to the end. If it's gunked up or not moving freely it will cause exactly what you are observing. That clicking sound is it half engaging.
Bryce.
Thanks for the reply. I see the part you are referring to and assume this is what handles the auto stop?
It doesn't look dirty. When you say it is meant to move freely, you mean the whole mechanism which has the heads on? I could try and grease this to see if it helps?
Looking at how the mechanism moves I asusme greasing these areas?
I took some additional pictures to see if anything looks obvious?
(https://live.staticflickr.com/65535/52877636723_564f273bd8_b.jpg)
(https://live.staticflickr.com/65535/52877636728_847821924c_b.jpg)
(https://live.staticflickr.com/65535/52877636718_a178e0a4f1_b.jpg)
(https://live.staticflickr.com/65535/52877348264_c6c4943199_b.jpg)
I just watched this video at position 9:45, and I can see that the white plastic bit moves from a left position to straight.
Mine does not move at all. It stays in exactly the same position. What causes that to happen?
Almost. Yes, it's the autostop, but it (should) move independently on the arm I've marked here in red. If this arm is jammed and the white wedge isn't resting in the correct position it will permanently autostop the motor as it is doing with yours.
Bryce.
Some good news, and some bad news.
The arm was jammed. By manually moving it up and down, it has freed it and it is now acting correctly when pressing play and the tape is no longer auto stopping, and is turning tape ok
The bad news is that I hear no sound out of the speaker even when turned up to the max. I pressed Delete on the keyboard and I can hear a faint beep.
What I've done so far is read continuity from one side of R114, 115, 116 on the motherboard to check it gets to pin 7 ok at the tape connector and its ok
From there I've gone from pin 7/G to C314 on the tape PCB.
EDIT. I got this wrong. C314 to the resistors are ok
Looks like you've cleared the first hurdle! I'd check for bad solder connections next, then I'd concentrate on electrolytic capacitors.
Bryce.
Quote from: Bryce on 17:35, 07 May 23Looks like you've cleared the first hurdle! I'd check for bad solder connections next, then I'd concentrate on electrolytic capacitors.
Bryce.
Absolutely spot on Bryce. Reflowed the tape PCB in the sound in section and tape drive is fully working now :) :)
Thank you very much for your help!
Quote from: Purity on 19:12, 07 May 23Quote from: Bryce on 17:35, 07 May 23Looks like you've cleared the first hurdle! I'd check for bad solder connections next, then I'd concentrate on electrolytic capacitors.
Bryce.
Absolutely spot on Bryce. Reflowed the tape PCB in the sound in section and tape drive is fully working now :) :)
Thank you very much for your help!
Excellent, congratulations!
Bryce.
Sadly this is still not working :-( The tape drive is functioning but I am not hearing any sound from the tape and it's not loading any games. I previously reflowed the deck and this seemed to do the trick, but now not working. I changed all the caps apart from two - the 0.47uf one as I didn't have any and the non polar cap in the middle - can i change this for a polar cap of the same value?
Pressing the del buton i can hear a sound
Quote from: Purity on 15:41, 20 May 23Sadly this is still not working :-( The tape drive is functioning but I am not hearing any sound from the tape and it's not loading any games. I previously reflowed the deck and this seemed to do the trick, but now not working. I changed all the caps apart from two - the 0.47uf one as I didn't have any and the non polar cap in the middle - can i change this for a polar cap of the same value?
Pressing the del buton i can hear a sound
Definitely not. If it's non polar then it needs to be non polar.
Bryce.
Quote from: Purity on 14:04, 07 May 23I just watched this video at position 9:45, and I can see that the white plastic bit moves from a left position to straight.
Mine does not move at all. It stays in exactly the same position. What causes that to happen?
Very good instruction...
xesrjb
If I put a sound probe on pin 12 of the LA6324 should I hear the tape drive? and if not, then it could be a problem at pin 8 wokring backwards to the tape head?
I *think* I have made some progress with this potentailly.
I hooked up an audio probe to the board at the same time I was pressing the DEL key and also when I was running a tape.
Both sounds are fairly loud until I hit the following points:
(https://live.staticflickr.com/65535/52934431724_197c882616_c.jpg)
I've marked out where the sounds are decent and where the sound goes quiet. I've measured all resistors in circuit.
Based on what I see here. I would guess it's the cap at C316 for the tape drive OR IC302?
For the DEL key sound I would guess it's probably the cap at C312. Resistors measure ok in cricuit and the sound fails on one side of R303
Thoughts?
(https://live.staticflickr.com/65535/52934873238_26fef37e89_c.jpg)
(https://live.staticflickr.com/65535/52934426166_e40693bf40_c.jpg)
That could indicate that the 6324 has failed or isn't getting power.
Bryce.
Quote from: Bryce on 09:58, 31 May 23That could indicate that the 6324 has failed or isn't getting power.
Bryce.
Thanks for your input. I'll check the voltage, and then change caps 312 and 316. If that makes no difference I'll change IC302
Watch out for this one, if the screw is tightened too much it can crack the power track to IC302.
See the crack in the PCB indicated by the arrow.
20220710_122553 (1)~3.jpg
Absolutely spot on again Bryce. It was an issue with the voltage. I was reading 0.8v on pin 4 of the 6324. There was 5v at the connector so I measured at R306 and C315, and suddenly the sound began to be be at the correct volume. I reflowed both components and it seems to be consistent now. Thanks for the help!
Thanks Rabs. If it continues then I will check this
Then congratulations again. Looks like it should be fully working now. However, neither of those components are responsible for the voltage to the Op-Amp, I'd check/reflow all joints around that area, especially the Op-Amp pins.
Bryce.
Quote from: Purity on 21:15, 31 May 23Absolutely spot on again Bryce. It was an issue with the voltage. I was reading 0.8v on pin 4 of the 6324. There was 5v at the connector so I measured at R306 and C315, and suddenly the sound began to be be at the correct volume. I reflowed both components and it seems to be consistent now. Thanks for the help!
Thanks Rabs. If it continues then I will check this
Good to know...
xesrjb
Quote from: Bryce on 08:58, 01 June 23Then congratulations again. Looks like it should be fully working now. However, neither of those components are responsible for the voltage to the Op-Amp, I'd check/reflow all joints around that area, especially the Op-Amp pins.
Bryce.
Yea I understand the voltage is at C on the connector. I think when it was measuring 0.8v a pin 4 of the 6324 I was still seeing 5v at the connector, and when i touched R306 and C315 it stared working and I heard a noise at the speaker that indicated that the volume had changed. I reflowed these pins and I switched it off and on, probably around 20+ times and couldn't get it to fail. If it happens again at least i know where the fault is and can reflow other bits. Thanks for your help!
Ok, then we'll consider that as fixed. :)
Bryce.