Just finished my DAC 1541A kit, checked all the voltages
L1 = 5V
L2 = -13V
L3 = -5
L4 = 5
L5 = 5
L6 = 5
C29 = 15V
C30 = 15V
All chips sit ok in the IC sockets. I have made sure pins sit inside the sockets
用CD player's coaxial 連到 DAC1541A, 無聲出.
再 用CD player's coaxial 連到 另外Lite DAC, 有聲出.
用我的示波器check output. 看見有Hi frequency output, 但不像audio.
有 無人可幫一下??
Thank YOU!!!!
Output of the power transformer marked 16v - 0v - 16v.
I measured that 20v - 0v - 20v.
After the diode,
I got 26V.
R11 = 13.9V
R12 = 12.7V
R13 = -13.7V
R14 = -12.4V
I will try to get some VR to replace the 2.2K resistors to get -15V.
So, the TDA1541 won't work if the voltage is lower than -15V? I The Spec said the min Voltage is -14V.
I have bought 3 kits from China before
My experience was :
1) There was a ONE wrong location marking with the "Component Mark" of 1.8K resistor. This made it open with the Opamp IC. But it only happen to one channel. (New ver. might already corrected)
2) Do you know that :
Hi KK sir,
I will try feeding the coaxial signal direct to CS8414.
For Old Boy,
I am using
R25 --> 475R
C33 --> 0.047uF (Could not find 0.068 in the parts. Found only 0.047uf)
C35 --> No component. for my CS8414 PLL filter.
Please check with the diagram. And connect as like this.
RE-plot the waveform again and show it.
FYI:
We have 3 class about using this board also no problem, can you use our supplied components to assemble first, once OK, you change to yours as you like.
Did other people need to make this change too?
This change looks a bit difficult to make on this PCB, but I will try.
Would that be just a bad CS8414?
I have another DAC using the same CS8414. I will use this chip on the other DAC to check if the CS8414 is good or not.
I didn't do that before because the other DAC Kit is very expensive.
Finally the DAC works now.
Thanks for everyone's help. Especially KK Sir!
Here is what I did.
Yesterday, I went to buy a 0.068uf cap.
I couldn't find the 0.068uf cap in the kit, so I used the 0.047uf that came with the kit. That is why the CS8414 could not lock the input signal.
I changed the C33 to 0.068uf. Everything works now!!!!!!
I didn't know that small difference can change the PLL filter that much!!!
For autumnleafacat:
I bought Tek 465B scope on Ebay for $60 USD.
Troubleshooting this DAC kit was painful and also fun.
I have learned a lot more this way. (Happy!)
It's fun to use the scope to probe each pin and make sure each Chip is working ok. I had no idea of CS8414 before. Now, I have a little more ideas what each pin should output. Reading the schematics of this DAC and pin-out of each Chip was a good learning experience.
Hi AlfCat,,
HK$1,200 is not too bad .
I bought mine 2 years ago. I really used my scope this time for the DAC kit. I just played around and learned to use it. I can't live without it when DIYing.
I can't wait to work on my next audio kit project. Hope Hififever makes more kits!!!
I breed the female BSH as shown. She won lots of prizes in cat show.
May I know where to buy a trusty analog Tek scope in Hong Kong. I also search on ebay for a 2445 150MHz 4ch scope. But the shipping charge cost as much as the scope. I had been 2nd hand test eqiup shop in KwunTong and Mongkwok. They told me some Tek scopes are broken and they sell it "as is" even at HK$10,000. I wondor I could get a Tek analog scope in good condition at a fair price in local.
Wow, you are a cat breeder? There aren't too many BSH breeders in Hong Kong. Your cats must be very expensive.
I got mine at eBay too. Fortunately, he is located in Hong Kong. I can only recall his name as Mr. Tam. He sells a lot of analog equipment like the Tek Scope. Unfortunately, I can't dig back the information from eBay anymore.
You are right in a sense that shipping to Hong Kong cost as much as the scope itself. I was kind of lucky that time when I got mine. Unfortunately, he didn't give me a card. Will see if I can locate him for you ....
Similar to hifi audio, breeding cat is only my hobby. However the adoption charge can cover the expense of attending shows.
Thanks for your help on my Tektronix analog scope searching. I will keep my eyes open on ebay once the Hong Kong seller surface.
You know the Tek 465 is the last scope they made using standard IC, which is maintainable lifetime, even including the CRT. For the analog scope mft after the 465, Tek used custom IC that the scope can be serviced as long as old stock custom IC last. Once broken, all finished.
I thought of a last resort ---- I dug up my emails to search for the invoice the eBay seller sent me for payment. Wa La ... it is there!
I sent an email to him asking him whether he got more of those Tektronics scope or not. On his current listing, he got other stuffs but not oscilloscope.
All guys pursue old Tek analog scopes because only analog scopes tell the truth. The component datasheet only shows waveform photos taken from analog scope, but not using data captured by digital scope. The Aliasing Error in digital scope limit the accuracy of high frequency information when in slow time-base. This was my past experience.
The seller IVAN says he got two other Tektronics scope for sale ($1500 to $ 2500, depending on model). You tell him you are Alfred's friend at St. Joseph's and you know that I have bought the 465B from him somewhat around June this year.
Please send me an email at achan@sjc.edu.hk and I can forward Ivan's email to you. You two can deal directly because I don't know what model suits your need.