GF-777 Advice please

[mtb_ed]

Hi all, as some may know from previous posts I have become a proud owner of a Gf-777 and I'm loving every minute of it.

But I just wanted to seek some advice, is there anything I should do to out of service before using it too much.

I will be looking at cleaning it by stripping it down etc. `but I heard people mention about recapping? etc

Any help appreciated

Ed

 

[mmcodomino]

Never change a running system.

 

[BoomboxLover48]

Ed,

Enjoy the unit!
There is no need for recapping the unit if it is working fine.
Fatdog put very nice instructions on opening up the unit and changing belts.

 

[bklyn sound]

Ed,

Enjoy the unit!
There is no need for recapping the unit if it is working fine.
Fatdog put very nice instructions on opening up the unit and changing belts.

If it ain't broke don't try to fix it.....

 

[Cpl-Chronic]

Well, recapping can improve bass & treble response if yours sounds flat but it takes alot of work, audio grade caps, lots of solder & a good solder remover. Also, you have to have very steady hands & you ahve to be sure to not overheat or damage other components with the iron. If you are not a very experienced electronics repair person, you probably shouldn't try it tho.

Good luck if you decide to try it. Other members did a recap & they swear it improves the sound.

 

[wills15]

Ed,

Enjoy the unit!
There is no need for recapping the unit if it is working fine.
Fatdog put very nice instructions on opening up the unit and changing belts.

If it ain't broke don't try to fix it.....

Disagree. Recapping will almost definitely improve the sound of any thirty year old amplifier. I have found it's made a big difference to every box I've done.

Forget audio grade caps, these didn't have expensive caps in them from new. Just make sure you get a reasonable brand.

 

[tshorba]

I disagree with the "ain't broke" crowd, you service a car before your broken down on the side of a Hwy don't you

Modern electrolytic capacitors are only rated for 3000 hrs (max) this lifespan varies with heat and ripple current so it can actually be dramatically less. The caps used in boomers back in the day were much lower quality and by now all would have drifted from spec as the electrolyte dries/leaks. The electrolyte is also an acid base so if it leaks it can cause further damage to the board.

With older transistors and IC's becoming harder to find (and knockoffs) there is no better time to consider making your box last longer by doing some Preventive maintenance on it. As noted in a number of discussions on here in the past the SQ between two members boxes of the same model can greatly vary due to the degradation of internal components. Now whether an individual can "hear" a difference before and after recapping is subjective, some will some won't.

 

[BoomboxLover48]

Electrolytic capacitors in early 80s boomboxes are still working so well in many brands including Sharp, JVC, Panasonic, Pioneer, Toshiba, Aiwa, Sony, Marantz, Lasonic, Conion, Akai etc.;

I have never seen a leaky or swollen caps in any of my more than 60 boomboxes I have. I have seen leaky and bad ones in tube radios from the 60s, but still majority of the replaced ones were still good when checked for values and was within acceptable the range.

I've only heard of Hitachi 8600RM notorious for capacitor issues affecting performance. My Hitachi 8600RM still sounds like a brand new box. These boomboxes kept in temp and humidity controlled rooms gave fewer issues with cap problems. The extended use and environmental conditions will accelerate the ageing process. I would say most of us have decent low hour boomboxes in our collection.

I think the Capacitor plague started with Taiwanese caps made in the early 2000. http://en.wikipedia.org/wiki/Capacitor_ ... lectrolyte


I do admit that it will be a good idea to change all the caps. But in the grand scheme of things we are overdoing the maintenance. If someone fools around in teh RF stage and do recapping it will completely throw off the alignment. Just recapping alone will not maximize performance, after that we need to complete the alignment also. Not many people have that capability of tune ups. In many cases people do more harm to other components than any good.

This kind of over maintenance is good for folks who have a few boomboxes and will make the collectors with lots of boomers go bankrupt!

Just my opinion!

 

[tshorba]

My Hitachi 8600RM still sounds like a brand new box.

Subjective opinion

These boomboxes kept in temp and humidity controlled rooms gave fewer issues with cap problems.

No humidity and not many temp controlled rooms in OZ(AC & heating vary the temp a lot so don't count), most boxes are out of peoples sheds & spare rooms.

I think the Capacitor plague started with Taiwanese caps made in the early 2000. http://en.wikipedia.org/wiki/Capacitor_ ... lectrolyte

Example of high quality manufacture with cap issue way before the above date

"Which units are affected?
The only Naks that are NOT subject to orange cap disease are ones made before 1978. For tape decks that would be the 250, 350, 500, 550, 700, 700II, 1000 and 1000II. All of the rest are potential Orange Capacitor Disease units."
http://www.nakremotes.com/Geo/Scott_Nak_FAQ.htm#Orange Cap Disease

 

[Cpl-Chronic]

Electrolytic capacitors in early 80s boomboxes are still working so well in many brands including Sharp, JVC, Panasonic, Pioneer, Toshiba, Aiwa, Sony, Marantz, Lasonic, Conion, Akai etc.;

I have never seen a leaky or swollen caps in any of my more than 60 boomboxes I have. I have seen leaky and bad ones in tube radios from the 60s, but still majority of the replaced ones were still good when checked for values and was within acceptable the range.

I've only heard of Hitachi 8600RM notorious for capacitor issues affecting performance. My Hitachi 8600RM still sounds like a brand new box. These boomboxes kept in temp and humidity controlled rooms gave fewer issues with cap problems. The extended use and environmental conditions will accelerate the ageing process. I would say most of us have decent low hour boomboxes in our collection.

I think the Capacitor plague started with Taiwanese caps made in the early 2000. http://en.wikipedia.org/wiki/Capacitor_ ... lectrolyte
...

Just my opinion!

I think you're right. Looking inside my GF I could not find 1 bulging, leaking or discolored cap anywhere & things sound loud, clear, crisp & balanced so I think my triple7 is 'A-OK'. I build PC's & test RAM, CPU's etc. & YES it was a major manufacturer of caps who stole a formula from another major company but it was inclomplete & the errors in the formula caused the caps to bulge, leak & pop. That was back around 98' actually & mostly affected computer boards, if I remember right.

Again, my triple7 sounds massive with the right speakers & I get a reasonably decent sound bordering on home stereo quality so for me, recapping would be a waste as, in reality, the difference in sound would be negligable. The triple7 had horrible woofers & tweeters but as soon as you find the right combo of drivers to replace them, it comes alive without having to touch the electronics.

On the other hand, if you are having problems with getting good sound from your blaster & the speakers chceck out OK, a recap might clear up problems with stereo balance, treble & bass response, low max volume, etc. Also, if you want a more balanced mid frequency response from the horns on the Triple-7-Z, open them up by replacing the 4.7uF tweeter caps with 12uF caps so that they dip lower into the 3-4Khz zone & overlap with the outer woofers more seamlessly & naturally.