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200 Series General Forum for the Volvo 240 and 260 cars |
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CR-4024/CR-4123: The Definitive ThreadViews : 3926 Replies : 26Users Viewing This Thread : |
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Thread Tools | Display Modes |
Oct 26th, 2022, 10:56 | #21 |
240 Turbo
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Thanks for the reply, I already checked the fuses and they are fine. The frustating thing with this unit is it worked perfectly the last time it was installed and I only took it out because I wanted to play some CDs in the car. since then I have started using a smart phone and discovered the wonder of bluetooth so the CD player is now no longer required.
I'm not into electronics so I won't be going any further with this head unit, I've ordered a cheap replacement unit that has bluetooth and FM radio for £18! that will do for me and will plug in to the amplifier I have with no trouble.
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1991 240 Turbo GL 1992 940 GL 1996 940 GLE Turbo Auto 1985 Bedford CF2 B230E |
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Nov 8th, 2022, 23:50 | #22 |
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Removing The Faceplate
Firstly, a quick thanks to Suterman for donating his unit to the cause, I have been able to delve further into the unit with slightly less concern about breaking 'the only one'.
The faceplate on these units is a single moulding (no separate bezel and/or fascia like with the CR-7xx or CR-9xx units). As a result, it can seem daunting to attempt to remove it, but the process is actually remarkably simple - the only items holding the unit captive are the power/volume knob and fade control ring, the tuning knob and band selection ring, and the cassette direction/eject switch. The removal process is detailed below:
Following this procedure, one should now have access to the PCB containing the VFD display, the station memory buttons, and a selection of bulbs. It should be worth noting that the cassette direction indicators (arrows) are actually formed (triangular) LEDs and NOT filament bulbs like all the others. Finally, do NOT attempt to remove the display/button PCB. There are (at least) TWO flexible connectors to this board, one of which is on the bottom side of the main board, and one of which is sandwiched underneath the power/volume switch. Trying to simply pull this board and 'hinge' it down will snap the latter flexible connector. I am still working out further disassembly steps... It's bloody complicated and rammed full of stuff. |
Nov 9th, 2022, 20:58 | #23 |
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Removing The Mainboard:
Removing the mainboard (the bottom PCB, as shown in the attached image) is not necessarily a complicated process, but it does require a degree of patience and a gentle hand. The process is outlined below.
In addition to these steps, one does need to have already completed "Removing The Top Plate" (post #7), "Removing The Bottom Plate" (post #8), and "Removing The Faceplate" (post #22).
Through tearing this unit apart, I am discovering that it is not nearly as intimidating and 'unserviceable' as I initially thought, it's just not at all obvious how it comes apart initially. The turning point was certainly removing the faceplate as discussed in my previous post. Alternative Links: https://drive.google.com/file/d/1dsU...usp=share_link https://drive.google.com/file/d/1Btj...usp=share_link |
Nov 21st, 2022, 21:22 | #24 |
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Removing The Main Board - Correction:
My bad, I missed out some stages in the process of removing the mainboard in post #23, please follow these steps and consider that post superseded.
In order to carry out this work the following stages need to have been followed:
Once these steps are completed, the following must also be done:
Apologies for having to make this correction, but hopefully this prevents damage to other units, and provides a more efficient method for removing the mainboard. It should be noted that simply removing the mainboard grants the user access to practically every aspect of the unit - the mainboard itself, the other PCBs in the 'top half', the cassette deck screws, and hence the auto-reverse board and tape-head board attached to it. Alternative Links: https://drive.google.com/file/d/1U8-...usp=share_link https://drive.google.com/file/d/15I6...usp=share_link https://drive.google.com/file/d/1DAI...usp=share_link https://drive.google.com/file/d/1mqz...usp=share_link https://drive.google.com/file/d/12-x...usp=share_link |
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Dec 16th, 2022, 16:46 | #25 |
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I just powered up the cr4024 in order to test the din outputs, it worked, then did not work and appears to have died.
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Dec 17th, 2022, 21:31 | #26 |
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Define "appears to have died"? As in the display no longer powers on or anything? Whilst it is possible that probing the DIN outputs could cause unit failure, it is very unlikely, I mean, a human finger is far more 'dangerous' from the electronics' perspective than a DMM or oscilloscope - lower resistance and higher capacitance producing far more severe ESD (electrostatic discharge - essentially a static shock that can damage electronics before it becomes feelable to humans).
More likely it is just coincidence as these are old units now. As an aside, if the display does still illuminate, try turning the volume to maximum - you may be able to hear audio very faintly, in which case the preamp might be 'nuked'. Having said that, you should still be able to hear the speakers 'pop' as the external amp gets turned on... I guess if not, then perhaps it's the control signal and/or associated circuitry that has failed. Equally, it could be coincidence and simply a dry capacitor, corroded PCB trace, cracked solder joint, etc.
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1990 Volvo 240 GL Auto "Catalyser" (oOOoh, fancy). B200F, about as original as they come, and all in BLOO. ~140k
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Jan 4th, 2023, 19:10 | #27 |
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CR-402x/405x User Manual Scan:
Against all conceivable odds, my friend has just purchased a Volvo 760GLE, and in the glovebox, in the book pack was the user manual for this lineup of stereos. I have since scanned this and converted it to a PDF. A compressed version is attached directly, but a higher-quality version is linked below.
Alternative Link: https://drive.google.com/file/d/1Jhf...usp=share_link |
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Tags |
240, cr-4024, cr-4123, head unit, stereo |
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