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Quad 77 CD player laser mech`.
Quad 77 CD player laser mech`.
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Old 23rd April 2018, 11:49 AM   #1
Pioneer44 is offline Pioneer44  United Kingdom
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Default Quad 77 CD player laser mech`.

Hi,

Looking for some guidance with a Quad 77 cd player.

I recently acquired a 77 cd as part of a deal ,which has problems. The player will not recognise cdr/cdrw or any disc which is scratched but plays new/unmarked discs perfectly. Having spoken to Quad service department today they inform me the Philips 12.4 laser mech` hasn`t been available for some time and they have to use reclaimed (secondhand) parts from other players ! This player was serviced by Quad in July last year (internal sticker) when a replacement laser mech` was installed but they won`t honour the 12 month warranty as I`m the new owner. They are prepared to fit another (used) laser mech` which "may or may not allow the player to play cdr/cdrw and scratched discs" at my cost, but what`s the point of throwing money at the problem when there`s no guarantee ??

Has anyone any experience of this player or more importantly replacing the laser mech` ? I can find brand new laser mech`s on Ebay from between 20 and 55 but would like to know what sort of a job replacement is ? Quad say it`s a very difficult procedure and don`t advise me to attempt it. I`m a sparky by trade with many years experience of repairing/working on audio equipment and it seems a shame to scrap a mint cd player which sounds lovely when it`s playing new cd`s.

Any suggestions gratefully received.
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Old 23rd April 2018, 12:00 PM   #2
Mooly is offline Mooly  United Kingdom
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Quad 77 CD player laser mech`.
I'm not sure the CDM12.4 will cope with CDRW but it will certainly work with decently burned CDR.

As always, the first thing to do would be to look at the RF (eye pattern) when playing a perfect standard disc and make a judgement on the amplitude and overall quality. Its impossible to say whether there is a real problem or not without doing at least some basic tests. Amplitude on a scope should be around 1.2 to 1.5 volts peak to peak.

My experience was that the 12.4 was never brilliant with severely damaged discs although it would play all the simulated defects on official Philips test media. Given undamaged standard discs it should be faultless and I also found it to be so on countless CDR I burned.

My own personal experience of the 12.4 was in a MicroMega player, but we also replaced 12.1's and 12.4's like they were going out fashion back in the mid 1990's. Most of the problems with the originals were down to the grease used on the mech and ultimately this was fixable with a stripdown.

This far down the line and there is no knowing what is fitted to your player... you have to test it with a scope and make sure the quality of the signal is good.
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Old 23rd April 2018, 02:17 PM   #3
Pioneer44 is offline Pioneer44  United Kingdom
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Hi Mooly,

Thankyou for your reply, but unfortunately I don`t have a `scope so am unable to test the presently fitted laser. There does seem to an issue with the player which suggests a new laser mech` would be the only cure hence my questions about ease of fitment (or if there`s anyone local who could change it).

Many years ago I owned a 77cd player (mains version) and don`t remember that having difficulty playing cdr or lightly scratched discs, so there is definitely a real problem with the current player.
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Old 23rd April 2018, 06:39 PM   #4
Mooly is offline Mooly  United Kingdom
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Quad 77 CD player laser mech`.
Your big problem would be getting a known good replacement. Remember these pickups are twenty years old now and the stuff on offer is generally of extremely poor quality i.e. poor copies and/or reclaimed stock. The last of the genuine parts disappeared well over a decade ago. Also, replacing just the pickup is a bit more involved (more stripping down) than just replacing the pickup + sub chassis (mech) that contains the pickup and motors. The latter is normally what is ordered but pickups were available separately.

Post #10 here details what is involved on a MicroMega which almost certainly has the same loader assembly

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Old 25th April 2018, 10:18 AM   #5
Pioneer44 is offline Pioneer44  United Kingdom
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Thankyou for the link to swapping the laser/mech.

Unfortunately as of last evening the player won`t play any cd whatsoever, it just reads "err". I guess the previous owner knew the laser was on the way out and genuine replacements are no longer available so off loaded it as fast as he could once it started to dislike cdr and scratched discs. He also said the 77 has never been able to read cdr/lightly scratched discs which was also untrue - I really must stop trusting the "reasons" sellers give for the sale of an item.

I`ll just have to put this one down to experience and scrap an outwardly unmarked cd player as I`m not prepared to waste time and money fitting a replacement laser as there are no original Philips 12.4 mech`s available and the popular opinion on what is available now is they are not good quality. Neither were Quad service of any help either.

Think I`ll stick with ye olde vinyl .
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Old 25th April 2018, 11:37 AM   #6
Mooly is offline Mooly  United Kingdom
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Quad 77 CD player laser mech`.
Its a shame but I think realistically we have to accept that the CDM12.4 is getting on for quarter of a century old now and that good quality 'plug and play' replacements just aren't available anymore.
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