Garden watering system.

I will be away for a few days and the seedlings can't be let to get dry at this time of the year. Not much time and I as always work on a budget:  Reviewed the timer tap controllers and sprinklers. Picked a controller from Jaycar and tried a rotating lawn sprinkler.

I thought if the timer software is not good but the hardware is Okay I might gut it and replace it's brains with a Arduino type controller then get all sorts of remote control. The hardware seems fine so far though and the software too. Lets leave it at that for now.

The lawn sprinkler just did not work and stuck after half an oscillation. I returned it an got a simple cone spray that is meant to stick in the lawn. I mounted it upside-down over the main garden and used the timer to set it running for 15 minutes at 6 am and 6 pm. It seems just fine for late spring and did a great job while I was away for 5 days.

Control unit and sprinkler.
 

I might tap into the hose that runs along side of the house with some screw in spray nozzles to water some potted plants to the along there. I put these pots in the empty spots of the garden under the timed sprinkler while I was away and that worked out well but I need that space to let things grow so the pots need to go back.

Then

Now

 I now own an 8 Track player

So I just found an 8 Track Player.....

 A Prinzsound CRD8, Serial # 001429 (thanks man)

I spent a bit of time on it to get it going nicely and it does now. Information on it is very sparse to the point were the above post was the only reference I could find on it.

I want to do a fairly complete post on the fix so that web can preserve the info in case others need it:

I opened the case and the hardware was all quite good. Heads nice and not even very dirty. Only one drive belt in the whole unit and that still has good tension. The power plug was loose so I tidied that up and plugged it in. 

No smoke or bad smells. Plugged in a David Cassidy 8-Track (the tape I cared least for was picked for testing) and it thumped into life ( really does thump. Big fat solenoids ) and plugged my 70 Technics EAH-220 headphones in.

Right channel fine, left channel nothing.

Got to be the rec/play switch. Stripped and cleaned with iso. No difference. Made a quick and dirty audio probe with a guitar amp I had to hand and found the signal disappeared in the left pre-amp just before the volume. 

No service manual to be found anywhere on the web. 

Drew a circuit and overlay then put it back together and started checking voltages on the left channel against the right. Second transistor in the left channel sus; replaced the 2SC871 with a BC549 . Sound in both channels but the left starts quietly then fades to full volume after 10 or so seconds. Replaced various electro' caps to no affect until I looked at the what I had considered the least likely electro which was the cap to the playback head. 

Replacing that fixed it and it now runs just fine. It was quite obviously swollen on removal and had interfered with the bias of the first transistor until the cap in the emitter path had charged up. Finally I put RCA plugs on in place of the DIN plug.

I'll post the overlay and circuit diagram I worked out in as follow ups to this post.

The only real lasting damage is that I now quite like David Cassidy. 

 

PC board overlay: Solder side.

 

 

Circuit diagram of the left channel :

 

2016-07 Concrete Record Player.

The Dual turntable needs somewhere to live. I decided to make this a test of the process for my ideal record plinth.
The Concrete Record Player (plinth.)

The process: Make a mold and fill it with concrete

The mount points for the turntable are precise and too thin for concrete so I made a frame of plywood to be embedded in the plinth the the turntable will rest on and mount to. I made two and laminated them together for strength and the depth needed for the turntable spring support cups.

The frame mounted on the top of the mold with the turntable cutout under it. The frame protrudes and that will keep it embedded in the concrete. Here I am packing out the interior with packing foam and masking tape to keep the void in the middle empty.

The mold with the sides on and some dowels for the mains and audio cables. I didn't want to risk cracking the plinth by drilling these out after it had set. The first  concrete is in and you can see the wire squares I added into the concrete hoping it will strengthen the final block.