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Quad 33


Quad 33 Our Standard Full Service (33FS)

Our UK  Quad 33 full service includes: PAT*, fault diagnosis, replacement of all electrolytic capacitors, out of tolerance components and a full performance test, PAT and 48 hour soak test.*  

The top image below shows a typical full service that costs just 130.00. Even better, if you have both your 3O3 and 33 serviced at the same time the combined charge will start at 220.  On the majority of 33s & 3O3s we receive from the UK, this is the final cost + return carriage. In some isolated cases  where  expensive or hard to procure parts are required, such as replacement switch banks, there will be an additional charge. If this arises we will notify you before we commence any work.

Standard 33 full service example

This particular 33 had noisy controls, hiss on the right channel and a low hum on both channels when set to 'disc'. In addition, the mains filter capacitor was burnt out, the 'radio 1'  PB switch was intermittent and the left channel popped in and out occasionally.  The indicator bulb had also blown.

Action Taken: First, the PCBs were removed and the PSU sub assembly dismantled, thus allowing access to the PSU board, the blown mains filter and the indicator lamp. Next, the full set of electrolytics (originals) and mains filter were replaced with new devices.   A new lamp was also fitted. The volume, tone and filter control  wipers and tracks  were cleaned using a high performance switch cleaner. With an oscilloscope, the hiss on the right channel was clearly visible on the output of the tone control section, but on the input side, the noise level was normal.  A faulty transistor, TR401 proved to be the culprit and this was replaced with a low noise BC184C. On close inspection of the Left PCB a dry joint on C403 was clearly visible. This was the cause of the intermittent left channel.  After removing the front of the chassis and  releasing the bottom PCB,  the push button channel selector switch bank was dismantled and the individual switch contacts were cleaned - a tedious and lengthy procedure but necessary due to the intermittent switch operation.   A full signal level, Flat & RIAA frequency response, distortion and Listening test follows. Finally a 'portable appliance safety test'  (PAT) is carried out.    

Some 33s we receive for service are in a very poor state. e.g., rusty case and front panel, paint worn on volume control knob 'Quad' legend paint worn etc... etc. We can restore the overall look by stripping and re-spraying these parts with primer and top coat. The re-sprayed sections will not be perfectly colour matched but it will certainly look better than the, ' fresh out of the dustbin', look!  The 33 volume knob when re-sprayed with will not have the original cream numbering and graduations. It will be engraved by hand to reveal the underlying aluminium i.e., silver. The cost for stripping the old paint, priming and re-spraying the case (sleeve) is 50.00 extra.

QUAD 33 Ultimate and full component replacement options

For the highest reliability and performance we can replace the entire set of resistors, capacitors and semiconductors on the seven circuit boards* including our full service for 250.00. This is a major overhaul using modern components, (1% tolerance low noise metal film resistors, polyester/polypropylene film capacitors, low noise high gain transistors.  Your 33 will be virtually new apart from the pushbutton switch bank, pots, transformer, and bare circuit boards.

We can also replace the active circuits with new high performance alternatives which fit into the existing slots to improve the overall sonic performance.   

*Not just the preamp and 2 tone PCBs, it includes, the often neglected,  motherboard, disc and tape components.


For full details of the ultimate 33 service CLICK HERE

Wish your Quad 33 had phono (RCA) and proper mains connectors? CLICK HERE


How to set up your Quad 33 After service

If you have just had your Quad 33 serviced or you have purchased one on the internet, here are a few tips to ensure it works correctly. The great looking, sweet sounding Quad 33 control unit has seven printed circuit boards. Two are fixed mother boards and five are slot in edge connected types. Two of the slot types are user configurable cards that slot in horizontally at the rear of the 33. The other three, slot vertically into the two motherboards inside the 33.
The plug-in design and lack of retaining springs means that the cards can easily work loose during transit. The main culprits are the vertically mounted cards. These often jump out of their slots and become wedged against the cover and their respective motherboards. When you first receive your 33 back from service, there are a few things to check prior to power up:
Details of how to hook up your Quad 33 HERE

* 'PAT' = Portable Appliance electrical safety Test   

** 'Soak testing' involves monitoring the signal output from all inputs for several hours to locate intermittent or impending faults. 



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Last modified: Monday, 27. April 2015 12:57