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Gambier Sound & Vision Repairs

Name: Gambier Sound & Vision Repairs
Address: 190 Commercial Street West, Mount Gambier, SA, 5290, AU
Telephone: +61405192134
Price range: Not Applicable

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Gambier Sound & Vision Repairs

Contact information, map and directions, contact form, opening hours, services, ratings, photos, videos and announcements from Gambier Sound & Vision Repairs, Electronics, 190 Commercial Street West, Mount Gambier.

Specialising in 𝗘𝗹𝗲𝗰𝘁𝗿𝗼𝗻𝗶𝗰 𝗥𝗲𝗽𝗮𝗶𝗿𝘀 ranging from: Circuit Board Repairs, Television, Audio, Home Theatre, Hi-Fi, Speakers, Guitar Amps: Valve & Transistor, Guitars, Keyboards, PA, Gaming Consoles: Sony PlayStation, Xbox & Nintendo Switch.

20/09/2026

𝗩𝗮𝗹𝘃𝗲 𝗚𝘂𝗶𝘁𝗮𝗿 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗙𝗲𝗻𝗱𝗲𝗿 𝗕𝗹𝘂𝗲𝘀 𝗝𝘂𝗻𝗶𝗼𝗿

Fender Blues Junior Amplifiers run their
EL84 output valves too hot from the factory, idling at 110% to 120% of their maximum capacity instead of the safe range under 70%.

Blues Junior excessive idle current design shortens power valve life and stresses the valve output circuit board. To solve heat, high-voltage filtration and factory over-bising issues, I always recommend to replace and perform the following:

All 4 high voltage filter capacitor replacement with quality capacitor brand as the original are poor.

Replacement of the Power Dropping resistor R47 2.2K ohm with a 2W Metal Oxide type. It is necessary to fit with a 5mm gap off the board as it drops substantial high voltage, and it runs incredibly hot, scorching the surrounding PCB.

Bias mod to reduce excessive idle current (piggyback) trick. Solder an 82K ohm resistor directly in parallel (piggyback) across the existing 33K ohm resistor located in the bias voltage stage.

Today's repair was exhibiting a low level and heavy distorted output. After completing the above steps and a thorough valve output board re-soldering, clean and voltage checks, a faulty output transformer was identified as the main cause of the low volume heavy distorted output.

Replacement output transformer was installed, final bias check completed and all pots and switches have been treated with contact cleaner. Amplifier has been repaired with perfect result.

16/09/2026

𝗦𝘁𝗲𝗿𝗲𝗼 𝗥𝗲𝗰𝗲𝗶𝘃𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗧𝗼𝘀𝗵𝗶𝗯𝗮 𝗦𝗔-𝟳𝟱𝟬

On the bench today another classic vintage Stereo Receiver from late 1970s golden era of hi-fi audio.

The Toshiba SA-750 is widely regarded by audio enthusiasts as an underrated gem that delivers warm, balanced sound compared to more famous models.

The amplifiers left Output channel has suffered a major cascade failure. When output transistors short completely, they almost always take the upstream components out with them, blowing your dual emitter resistors and voltage-feed resistors acting as unintended fuses.

The component - level rebuild involved replacement of shorted output and preamp transistors, open-circuit emitter and voltage -feed resistors, two burnt out PCB track repair and power supply / audio output stage re-capping. As the original Output and Pre-amp transistors are no longer available, a modern quality substitutes have been used. To keep the audio output stage perfectly balanced, updating the undamaged right channel with the same modern substitution transistors was also performed.

Finally bias voltage check and adjustment has been successfully performed on both output channels, voltage set at 25mV as per service manual.

Original indicator - dial lamps have been updated to modern LED types. All pots and switches have been thoroughly treated with contact cleaner. Amplifier has been restored with perfect results.

02/09/2026

𝗩𝗮𝗹𝘃𝗲 𝗚𝘂𝗶𝘁𝗮𝗿 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗩𝗢𝗫 𝗔𝗖𝟯𝟬𝗖𝟮

On the bench another VOX AC30 for a check up and comprehensive service.

Bias check indicated a 20mA current draw discrepancy on a EL84 power valve quad. When power valves are mismatched the one drawing more current will over-bias the others, severely distorting your headroom, creating heavy background hum, and radically shortening the life of the remaining good valves. Therefore a new quality well matched JJ EL84 quad set was installed.

Modern AC30s are designed and factory set to bias the EL84 tubes well past 100% of their maximum recommended plate dissipation of 12watts, by using a 50-ohm cathode bias resistor.

This is why I always recommend and replace the old cathode bias 50-ohm resistor with a 82-ohm resistor. By updating the cathode bias resistor to a 82-ohm value this delivers primary advantages such as power valve life which is significantly increased due to lower bias current draw causing the power valves to run cooler and giving a subtle tone shift a slightly “cleaner” sound with a bit more headroom. The Amp will still retain its iconic warmth but it will not break up into distortion quite as early as it would when biased scorching hot.

As the Vox AC30 amps run notoriously hot I also like to up date the fore 470 ohm carbon screen resistors to a 2watt rating metal oxide resistor, giving the resistor a larger operational buffer.

Reverb tank was also replaced as the original was non-operational due to open circuit transducer coil. To replace the reverb tank one of the speakers had to be removed to gain clear access for the reverb tank mounting screw. This was a good opportunity to remove both speakers and perform a check- up and clean.

All pots received thorough treatment with contact cleaner and final bias current check has been successfully performed.

Amplifier has been successfully repaired with perfect and enhanced performance.

27/08/2026

𝗦𝘁𝗲𝗿𝗲𝗼 𝗥𝗲𝗰𝗲𝗶𝘃𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗦𝗮𝗻𝘀𝘂𝗶 𝗚-𝟮𝟬𝟬𝟬 𝗦𝘁𝗲𝗿𝗲𝗼 𝗥𝗲𝗰𝗲𝗶𝘃𝗲𝗿

On the bench today another Gem the Sansui G-2000 classic vintage stereo receiver from the late 1970s golden era of hi-fi audio.

Receiver underwent a 𝗿𝗲-𝗰𝗮𝗽𝗽𝗶𝗻𝗴 process were all old electrolytic capacitors have been systematically replaced across the power supply, pre-amplifier and main amplifier stages.

After re-capping completion all power supply voltage rails have been verified and bias voltage successfully adjusted and set on both output channels.

All pots and switches have been thoroughly treated with contact cleaner. Finally the two traditional pilot lamps have been replaced with a blue LED types.

The receiver has been restored with fantastic results.

25/08/2026

𝗩𝗮𝗹𝘃𝗲 𝗚𝘂𝗶𝘁𝗮𝗿 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗠𝗮𝗿𝘀𝗵𝗮𝗹𝗹 𝟮𝟱𝟮𝟱𝗛 𝗦𝗶𝗹𝘃𝗲𝗿 𝗝𝘂𝗯𝗶𝗹𝗲𝗲 𝗦𝘁𝘂𝗱𝗶𝗼

𝗜𝗻𝘁𝗲𝗿𝗺𝗶𝘁𝘁𝗲𝗻𝘁 𝗟𝗼𝘂𝗱 𝗩𝗶𝗼𝗹𝗲𝗻𝘁 𝗛𝘂𝗺

On the bench a Marshall 2525H Silver Jubilee Studio Amplifier with an intermittent issue, emitting a loud hum after some time in use.

As the Amplifier did not reveal any possible fault clues, after performing all functions check and gentle individual valve tapping a dummy load, signal generator and oscilloscope was utilised to bench test and monitor amplifiers output signal.

After 1hr of bench testing the amplifier finally faulted, a pre-amp valve V3 was located to be the main cause of the intermittent hum.

Sometimes the very obvious can be tricky to find. A replacement with quality JJ ECC83s valve and comprehensive service has restored perfect operation.

17/08/2026

𝗩𝗮𝗹𝘃𝗲 𝗚𝘂𝗶𝘁𝗮𝗿 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗠𝗮𝗿𝘀𝗵𝗮𝗹𝗹 𝗝𝗖𝗠𝟴𝟬𝟬 𝗟𝗲𝗮𝗱 𝗦𝗲𝗿𝗶𝗲𝘀

On the bench another Marshall JCM800 for Re-Valve and comprehensive service.

I always recommend replacement of all 100k ohm plate carbon resistors in these models with quality metal oxide type resistor, as the old carbon resistors due to age often drift upwards in resistance causing multiple issues: from distorted sound to hiss, snap and pop described as frying bacon sound.

The two 220k ohm bias voltage feed resistors also often drift in value and can cause Power Valve bias mismatch. Therefore replacement with quality metal oxide resistors is also a must.

The two 10uf 100volt electrolytic capacitors located in the bias voltage stage also get updated with quality Sprague Atom Brand capacitor to ensure stable bias voltage supply.

Finally a complete valve set has been installed as pre-amp valves are becoming noisy and power valves are running 8mA apart indicating valve wear. All pots and jacks have been treated with contact cleaner and power valves bias current has been checked and adjusted to 36mA.

The classic Marshall has been restored with perfect results.

14/08/2026

𝗜𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗲𝗱 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗠𝗮𝗿𝗮𝗻𝘁𝘇 𝟭𝟭𝟱𝟬 𝗦𝘁𝗲𝗿𝗲𝗼 𝗜𝗻𝘁𝗲𝗴𝗿𝗮𝘁𝗲𝗱 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿

On the bench today for 𝗿𝗲-𝗰𝗮𝗽𝗽𝗶𝗻𝗴 (𝗮𝗹𝗹 𝗲𝗹𝗲𝗰𝘁𝗿𝗼𝗹𝘆𝘁𝗶𝗰 𝗰𝗮𝗽𝗮𝗰𝗶𝘁𝗼𝗿 𝗿𝗲𝗽𝗹𝗮𝗰𝗲𝗺𝗲𝗻𝘁) due to significantly lower audio output level from right channel compared to the left.

As electrolytic capacitors age they can cause audio distortion, low-frequency hum, loss of dynamic punch and weak or dull sound.

Today’s repair consisted of all electrolytic capacitor replacement located in the power supply / protection stage, preamp and the main audio output stages.

Once the re-cap has been completed, power supply voltage rails have been meticulously checked and adjusted at +43volts and -43volts. To stop cross over distortion, reduce heat and insure balanced and clean amplifier operation bias off-set and bias voltage adjustment has also been completed on both output channels.

Finally a new power indicator lamp has been installed all pots, sliders and switches have been thoroughly treated with contact cleaner.

Amplifier has been restored with fantastic results.

27/07/2026

𝗘𝗹𝗲𝗰𝘁𝗿𝗼𝗻𝗶𝗰 𝗖𝗶𝗿𝗰𝘂𝗶𝘁 𝗕𝗼𝗮𝗿𝗱 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗕𝗖𝗠 𝗿𝗲𝗽𝗮𝗶𝗿 𝗳𝗼𝗿 𝗡𝗶𝘀𝘀𝗮𝗻 𝗡𝗔𝗩𝗔𝗥𝗔 𝗗𝟰𝟬

(𝗜𝗻𝗼𝗽𝗲𝗿𝗮𝘁𝗶𝘃𝗲 𝗕𝗿𝗮𝗸𝗲 𝗟𝗶𝗴𝗵𝘁𝘀 & 𝗥𝗶𝗴𝗵𝘁 𝗛𝗮𝗻𝗱 𝗜𝗻𝗱𝗶𝗰𝗮𝘁𝗼𝗿 𝗦𝗶𝗴𝗻𝗮𝗹)

On the bench today a Body Control Module (BCM) for 𝗡𝗶𝘀𝘀𝗮𝗻 𝗡𝗮𝘃𝗮𝗿𝗮 𝗗𝟰𝟬 with inoperative brake lights and right hand side indicators.

Upon inspection a blown power management chip was located to be the main cause of the malfunction.

Replacement of the faulty power management chip and all connector pins including relay legs re-soldering have restored correct operation of the vehicle.

14/07/2026

𝗩𝗮𝗹𝘃𝗲 𝗚𝘂𝗶𝘁𝗮𝗿 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗠𝗮𝗿𝘀𝗵𝗮𝗹𝗹 𝗝𝗖𝗠 𝟵𝟬𝟬

(𝗥𝗲-𝗖𝗮𝗽 & 𝗥𝗲-𝗩𝗮𝗹𝘃𝗲)

On the bench another classic Marshall
Valve Guitar Amplifier 𝗝𝗖𝗠 𝟵𝟬𝟬 approaching 28 years of age, requiring capacitor replacement and a thorough service.

All high voltage filter capacitors have been replaced with quality F&T and TubeAmpDoctor capacitor brand. Low voltage power supply stage also received an update with new electrolytic capacitors.

Last and not least replacement of two bias stage capacitors was performed to insure stable bias voltage supply and two power valve coupling capacitors have been updated to a 600 volt rating to ensure and pre mote longevity and noise free operation.

All pots have been treated with contact cleaner and re-soldered. Finally all valves have been replaced with a quality JJ brand and bias current checked and adjusted to 36mA.

Amplifier has heen restored to a perfect condition.

10/07/2026

𝗩𝗮𝗹𝘃𝗲 𝗚𝘂𝗶𝘁𝗮𝗿 𝗔𝗺𝗽𝗹𝗶𝗳𝗶𝗲𝗿 𝗥𝗲𝗽𝗮𝗶𝗿𝘀

𝗠𝗮𝗿𝘀𝗵𝗮𝗹𝗹 𝗝𝗖𝗠 𝟴𝟬𝟬 𝗠𝗮𝘀𝘁𝗲𝗿 𝗠𝗼𝗱𝗲𝗹 𝟱𝟬𝗪 𝗟𝗲𝗮𝗱 𝗦𝗲𝗿𝗶𝗲𝘀 𝗠𝗞𝗜𝗜

On the bench recently serviced a 𝗠𝗮𝗿𝘀𝗵𝗮𝗹𝗹 𝗝𝗖𝗠 𝟴𝟬𝟬 amplifier that required a comprehensive overhaul due to its age exceeding 20 years, necessitating the replacement of several critical components.

The repairs included substituting the three main filter capacitors with high-quality F&T brand alternatives and replacing the 100K Ohm carbon plate resistors, which tend to experience increased resistance over time.

Additionally, two electrolytic capacitors in the bias stage were replaced to prevent bias voltage instability, and two power valve coupling capacitors were updated to ensure optimal performance in the high-voltage stage.

Furthermore, the amplifier's valves were replaced with premium JJ brand valves, and the bias current was meticulously adjusted to 36mA. A thorough treatment of contact cleaner was applied to all pots and jacks, restoring the amplifier to its optimal condition.

Address

190 Commercial Street West
Mount Gambier, SA
5290

Opening Hours

Monday	9am - 5pm
Tuesday	9am - 5pm
Wednesday	9am - 5pm
Thursday	9am - 5pm
Friday	9am - 5pm

Telephone

+61405192134

Website

https://www.facebook.com/gsvrmg?mibextid=ZbWKwL

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