Hacker Radios
Hacker radios, waiting for repair or sevicing, when completed they are taken to another workshop where they are tested for on air conditions
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.
Workshop with new test equipment in place
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 .
This is a jig I have made so the front cloth of a Sovereign is placed under controled pressure to allow at first trimming on the corners and then gluing into place. The difficulty lies in two parts, first ensuring minimum or no creases at the ends and secondly to trim off most of the remaining cloth after so that the thin white trim is flat against it when re-glued back into place.
An other factor has been about the original foam failing, which is quite correct. At first I tried different thickness of foam but all of them were still to deep to work.
The cloth showing signs of sagging is a combination of loss of foam but I think more to do with the material loosing it's abilty to stay stretched and over time the result is what we see, because when I have recovered the body without adding any other material to the backing there is no visiable difference or feel to the finish.
I should be working out a price for doing this soon, the side of the body's should not be difficult to do, the only problem will be the rear panel as this has an extra white cloth inside and sourcing this or equivalent will be rather difficult.
Only a couple of times I have found the thin plastic trim on the front and rear to be difficult to remove and these would be impossible to find apart from old stock peices.
Hacker Sovereign 11 470Khz IF's board realigned via Thuruby Thandar TG1304 fuction generator in sweep mode with marker signals connected to the medium wave coil and using the radio's demodulator diode the Tektronic oscilloscope is connected to the input to the volume control allowing a visual display showing the response of the board.
The RF alignment is undertaken by a Marconi TF2008 signal generator and monitored via 6 digit frequency counter.
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