ADVENT 300 Receiver Rebuild - Part 1

I've had this ADVENT 300 receiver hanging around for quite awhile and it's time to get busy on this project. It's not hard to tell it needs a little work.


 

I plan to improve on the cosmetic issues as you can imagine, but also plan to replace other parts to update this classic receiver that came out the year I graduated from high school. Back then I had a tube receiver that I scavenged from a Viking stereo console that an elderly neighbour was tossing out. She had had a tube TV catch fire and didn't trust them (tubes) any more so was going all solid state. She was still sticking with Viking, the Eatons house brand name though. Little did she know that almost 40 years later people still want those tube gadgets. But I digress...

The Advent 300 is still considered to be a great performer and even with its low power of 15 watts per side and kind of chintzy build quality it can rival much nicer newer amps. It's an FM tuner only (even back then AM sucked), and pre and power amp in one case, with jumpers between the pre and power sections so you can use it with other components or add an equalizer if you like.

This one has some stickers and scratches that have taken off the paint, rust damage, and just old parts. The voltage regulator has already been replaced but as far as I know it has had little servicing since new.





The old electrolytic capacitors are all going to be replaced in this project. I will also be trying to clean up or replace some of the fittings, for example the grounding screw and AC jack on the back are respectively rusted and cracked.

I'm going to clean extensively and might "reflow" solder joints. Essentially that means melting the existing solder to ensure that the contact is good. I will replace some of the jumper wires I think too, and clean up the routing in the process. Maybe I will anyway; I will certainly have a look at them and replace if questionable.







In the pic above and the one below you can see some of the rust on the case near the power supply and on the RCA connectors. I've actually removed a lot of the corrosion on the RCAs to the left already with a 3M pad and sand paper. The ones to the right are essentially untouched.





Here you can see the power supply. My first actual real "upgrade" is to replace the 2 large capacitors you see to the left. The stock components are 3000uf at 30volts but I will be using 4700uf at 50volts which is totally acceptable as a component value change for this area.



In addition to other resources, I am using the excellent website by David Eaton devoted to the Advent 300 as a reference. Thanks David!

http://www.davidreaton.com/Model_300_receiver_main_page.htm

I'll be back soon with Part II...

Ol' Shakey on the Swirly Table

Neil Young, a photo by Buhduh on Flickr.

I treated myself to one of my current favourite records on my current favourite turntable.

Neil Young, live at Massey Hall 1971 is an amazing record in my opinion. A man with a guitar, and sometimes a piano, in a hall with great acoustics and a reel to reel tape deck propped up on an office chair...what could be cooler than that?

Apparently this recording was "lost in the vaults" for 30 or more years before Neil decided to listen to it and eventually release it in 2007. Neil is a stickler for, and proponent of, high quality recordings including digital media formats. He didn't give this recording much thought but when he listened to it after many years he realized it was good and deserved releasing.

Deserved indeed. It's really good. Really really good. And I only discovered it a couple of months ago myself. Go buy it. If you can't get the vinyl, buy the CD or the DVD. Or get them all.

It sounds great on my newest turntable project and is a good showcase for any system. This "swirly table" as I have been calling it is a Technics Sl-1200 MKII that was in usable but battle scarred condition when I got it, but not anymore.



I can't stand the mess that DJ tables become. It's not just DJ tables but a lot of other too that people abuse. So I fix them up.

This one had already had the RCA cables replaced and obviously whoever did that had some idea what they were doing so I saw no reason to mess with that. I dealt with the cosmetic and other issues.

I took it apart and went to my friends shop with it with the intent of bead-blasting all the paint off but it turned out that the blaster was not working well. I got some paint off with it, but now I was kind of stuck, so I grabbed the angle grinder and a sanding disc and took the rest of the paint off. When I got it home a did a bit more controlled work with my Dremel and a sanding disc. I like the random swirly effect of this. I then gave it a few coats of a satin finish clear coat spray paint.





A few parts also needed replacing so I ordered them and I put it aside. It took a few months before I decided to get back at it and just the other day I put it back together. I had to get a trim piece for the pop-up target light, a new slider trim plate and ordered a lid and hinges. I also decided to order an LED kit but decided to just replace the pop-up light which was burnt out anyway and the pitch LED. The stock one is green but the new one is white. It's a bit too bright IMO so I will try to do something about that.

Anyway, here's the mostly finished product.



And the darn near completely finished item. It has the new parts mentioned above, a couple of new feet, and the heaviest thickest Technics mat. I even took an aluminum 45 RPM adaptor and "swirled" it with my Dremel. I still am going to tweak a few things but I really like how it has turned out.

From 66 & 2/3 to 33 & 1/3

I have not posted in awhile but thought I should start it up again. This one is about another Dual turntable problem and a solution for it. Hmm, that kind of makes it sound like Dual turntables have a lot of problems. That's sort of true, but they had a lot more turntables than most. More models and more in quantity sold too. Have a look at this page if you don't believe me:

http://www.dual-reference.com/tableinx.htm

So, the problem fix for the evening involved a Dual 510. The motor on the original version of the 510, and a few other models as well such as the 601 and 1249, had a tendency to run at twice the standard speed occasionally. This apparently did not happen on the Duals at home in Germany where the electricity from the wall is 240 volts at 50 HZ, but here in North America at 120 volts & 60 HZ it sometimes occurred. The motor in question was the SM-840. Later versions included the SM-840-2 and -4 and they had found a fix by then.

The motor runs at the right speed about 80% of the time and simply turning it off and back on usually makes it run at the correct speed. This is the second of these turntables I have had this issue with, and while you could live with it, I would rather make it go away.




The later motor model SM-860 also fixed the problem, and a kind person on Audio Karma sent me one very inexpensively.

With the turntable flipped over (yeah I know, the picture could be flipped too) here is the original motor. I took out the 2 large screws and 1 small one on the motor, and removed the cover for the electrical connections.



Swapping the entire motor is not required. You really only need to change the motor winding part which is off to the right in this pic. The entire motor can be taken out but there are several more screws and the pitch control belt to mess with if you do that. This is easier...sort of.



I often take close-ups of the wiring or other important details so I can make sure they go back the same way.



This is a good time to oil the motor bearings. Note the scarring on the armature. I'm not sure how that came about.



Top bearing with some fresh oil.



And going back together.



Fully reassembled, but I still had some fiddling to do. I found that there was a lot of stiffness in the motor and it barely turned under hand pressure and not at all with power applied. I played around with the tightness of the 2 bolts that hold the bearing mount and that did not help right away.




I swapped the armature from the 860 in place of the 840, thinking that maybe the scoring you see was a factor. The brass capstan was not at the same height though and I have trouble with those little screws before so changed it back to the original (on the right). This time when I put it back together it worked smoothly. It could have just been the orientation of the top and bottom bearings which are in kind of ball and socket joints.



Anyway, it all worked out! I cleaned the entire table up further, oiled the platter well, gave the lid a quick polish and here you go! Starting and stopping a bunch of times and the speed is just as it should be every time.



In this pic you can also see the cuing lever I made from a bicycle spoke and spoke nipple. That lever was missing as well and this stuff was handy.



It still has a few cosmetic issues but it looks good and works well.

Advent 400 Radio

I had another mini success story today. Someone on Audio Karma was asking for tips on how to repair his Advent 400 radio recently and it tweaked me into working on one of my own procrastination projects.

Aside: I would like to make "project" and "procrastination" into one word. Projectination? Procrastiject? I'm not sure either quite has the ring I want...

Anyway, the Advent 400 is a neat, high quality table radio with external speaker from c. 1975. The FM only tuner is supposed to be of very good quality and the fairly substantial (for a radio) speaker is quite decent. The tuner does appear to be quite sensitive. It has an auxiliary input and a tuner out so you can run a CD player or other device through it or send the radio signal to a larger amplifier.



The fellow on AK described a similar problem to mine, and that is very low, almost non-existent volume. I have had this radio for a year or 2 and even bought a batch of capacitors with this radio in mind, among other projects. Someone else chimed in on the thread there with specific capacitors to try first so I decided to go for it after work today.

As usual, I forgot to get pictures while I had the patient under the knife, but the operation was a success! I am listening to CBC Radio 2 right now and it comes in well with no antenna attached. The volume is all I could want from a table radio and the bass and treble controls work well. Tuning is vernier style which allows for accurate fine tuning.

I had a few minor glitches along the way. I ended up replacing 3 capacitors but at first only did 2, those being the ones closest to the volume control. Along the way I blew the fuse and had to solder a new one in. Also the caps I had were the right value but the wire leads were radial (both at one end) not axial (one out each end) so were a bit tricky to get into a tight spot. It all worked though and it is now working great!



Too bad about that little scratch on the face...




Edit: I found the new home for the Advent 400 in the dining/kitchen area at our cabin. It works over there and looks good next to the Dansk Kobenstyle coffee maker and those sushi plates (or whatever they are)

Holy Steuerpimpel!

It seems to be raining turntables around the home front, especially Dual turntables. Actually it has rained Kenwoods and Technics as well but that's for later.



I brought home for repair 3 different Dual 12XX series tables lately and in the last 2 days have worked on all of them. The 1225 has already gone back to the owner but I still have the 1228 I brought home yesterday and the 1242 from today. Even the ones that I still have I made progress on though and they should be working well soon.

Among other issues the 1242 above had a stylus that was nearly gone and the 1228 below had no stylus whatsoever. Both of them and the 1225 all had the most common Dual problems.

The mechanism of the Dual changers has a lot of moving, pivoting, sliding, rotating parts. All of those have some need for lubrication either by oil or grease. That lubrication gets dried and caked and stops doing the job very well. Another area needs little to no lubrication and in fact relies on just a bit of friction to operate.

That area controls the movement of the tonearm during the Start phase in automatic mode and the Return of the tonearm at the end of the record side. It relies on a steuerpimpel to do the job. A what? A steuerpimpel. It's a little plasticy bumper that sits on the clutch pin and slides against a platform taking the tonearm with it during the arm start and return action. When the needle is on the record it sits a bit away from the arm and the arms nearly friction free.

This pin is where the steuerpimpel goes. (Seinfeld to Costanza: "You just like saying that don't you?")



The steuerpimpel almost always fails after 30 years or so. The piece just disintegrates and breaks apart. When it does the arm won't move properly if at all. The part is also not that easy to find but also is easy to fabricate once you figure out what to use. I tried heatshrink tubing, small sections of the end of pen refills and other sizes of wire insulation but settled on 14 gauge insulation as it seem to provide good performance and fit.




16 gauge might work but 14 goes on easily and when cut nicely to the right length seems to work well. The 1242 has a longer pin and seems to prefer about 6mm long but the other 2 are best with 4mm. The key is that it should be just a bit longer than the pin itself so that the metal does not stick out. The smaller piece shown is about 4mm and the longer is around 6mm. Below is the longer one once installed.

         

I love simple fixes. That's not to say that every Dual turntable problem has a simple fix, but this one is not bad once you work out a few details.

Aside from that these turntables work amazing well after so long that I am starting to enjoy working them. I still have some other details to address on both the Duals sitting here but once again, another day...

Who needs Linear when you have Zero 100?

My latest favouritest turntable is this Garrard Zero 100. It is not quite my latest, and perhaps not my favourite but it's very close on both counts.

This was manufactured in the early 1970's. It addressed effectively the error that linear tracking tonearms also worked to resolve and that is that cartridges with elliptical styli (or any shape other than conical) would not always be at an ideal angle to the record groove.

Records are cut or mastered by arms that move at a tangent to the groove. Most tonearms move through an arc and present a different surface to the groove that can cause a different "interpretation" of the music trapped in the vinyl. Through careful alignment one can minimize this variance but it can't completely be eliminated with the conventional tonearm.

Above is an ad from an audio magazine dated August 1973 that describes how the Garrard Zero 100 addresses the problem. It does it very well and with a great deal of style.






The Zero 100 is another idler drive, much like many Dual turntables. It's also automatic and comes with a single play spindle and a changer spindle. The extra spindle and 45 adapter are stored in a little box under a wooden cover, reminding me of a cigar humidor.

The performance is great, though I have some small issues to work out. The manual switch does not always want to stay engaged for example. Also the lid is a bit funky and someone tried an even funkier repair on it. The lid is in 2 parts and the tabs that hold the smaller piece to the base had broken off and whomever had drilled through it in the wood base. I've got a plan to fix that but more on it later.

For the time being I really enjoy the look and it does not sound half bad either!

My First Record Meet and Her First Record!

Today I had a table at the Main Street Vinyl Record Fair here in Vancouver. This is the first time I have attended a record swap meet as a vendor though I have been to a bunch as a buyer. This event is a 2 day one this year and continues on Sunday. I won't be there tomorrow...unless I go back to shop!

I had fun and made a bit of money. However I wasn't there as much to sell records as most people. As I said in my last post, I was also selling turntables. I also advertised my services in repairing and providing advice on stereo systems. I gave out a lot of cards for AFishNeedsAStereo. :)

I did have a few boxes of records though and managed to whittle that down by about half. Someone I know thought they were doing me a favour the other day by giving me a box of records to take along. Being mostly kids music, James Last, Hooked On Classics and so on, that actually became a "FREE!" box. Thankfully almost all of that disappeared so I don't have many to drop off at the thrift store. I did hold onto a couple of Bill Cosby records from it though. Oh yeah, I also kept a Breakdance instruction record. I can't wait to start headspinning.

I had some good conversations with people, met some old friends, met some new ones and made some money. Giving away records was fun too. One old gent with a cane was chatting with me for a while though I could barely make out what he was saying as he had a soft voice and the speakers were too close. However the 86 year old did say he like spoken word records, so I dug out a Dylan Thomas album that I had priced at $2 or $3 and just gave it to him. It was probably the only record he acquired that day, even though he must have paid the $2 entry fee. 

And the little darling at the top also received a free record (from the free box). I am sure it is her first and though she had no idea what it was, she had a good grip on it and was hopefully going to hear it when mommy took her home.