Hacker ratio detector circuit being being aligned using a 10.7 Mhz wobulator and digital oscilloscope connected across the volume control, you adjust the controls to give a S curve representative of the ratio detector circuit on the oscilloscope, then align the IFT cores for maximum amplitude and linearity with the axis crossing the base line at 10 Mhz, if not or if your radio requires setting up the results are the "ssssssss" sounds on certain words, and can be effected  with loud passages of music again with strong local radio stations.

Spectrum anayiser,

I am often asked to repair the FM tuners in the Hacker radios, in the past Hacker recommended these to be returned to them, difficult of course these days.

I have found by using a spectrum analiser you can not only see as to what is happening in the signal path , but when replacement of aerial is needed, it is the best way to impedance match the common base input.

Unlike standard broadcast reception on medium wave/long wave, Fm tuners and the I.F boards do not have the same high gain stages, so matching and maximising the signal paths are more important

Image showing 10.7 Mhz sweep with centre marker using sweep generator. My preference when doing FM IF alignment is by placing a rf signal typical 100Mhz loose coupled in the workshop, this being received via the telescope aerial in closed postion  then connecting a HP spectrum analyser to the output of the rf tuner set up the oscillator, and first IF peak, then go through all the 3 off IF coils one at a time as they are all tuned at 10.7 Mhz. This way i can correct or locate low gain problems at each stage.

Service and repairs to Hacker radios

We offer a full and extensive repair and service on all the  Hacker radio range, using our own test jigs all we need is the chassis rather than the whole radio if you prefer, this reduces the risk of cabinet damage  in transit.

You may wish to do most of the repairs yourself and the radio just needs IF re-alignment, or perhaps you are looking at a potential purchase and might just require advice from us, not a problem just give us a call.

We repair radios for the trade and can offer a comprehensive service to ensure your sales are not limited due to time delays on servicing.

Radios can be sent to me for evaluation before any costings are involved, and unless the radio has been tampered with most repairs should not take to long to locate. With the large stock of spares we have most parts can be replaced;

we are currently developing a cabinet restoration service for the leather cloth in black and blue including replacing the sponge to give it that near new look .