I have onkyo reciever tx-ds898 no sound

Amazon.com, MyRemoteControls.com, and Remotes.com all sell a replacement remote for the TX-DS575. I have also seen the Onkyo TS-DS575 receiver with remote listed on eBay for as low as $35. Keep looking; the remotes are out there.

Do you mean ONKYO TX-DS484?

Read the manual which is available for free download after you register at retrevo.com.

http://www.retrevo.com/support/Onkyo-TX-DS484-Receivers-manual/id/365dj182/t/2/

This unit has a defective hdmi board,this is a common problem with this model. The unit is to be taken to a onkyo service center for exchange of the hdmi board under warrenty, if out of warrentyit will cost you several hundards of dollars.

THEY USE A MEMORY CAP.ITS LOCATED ON THE MAIN PCB ASSEMBLY, REF. C7701 ONKYO PART NUMBER IS 3000078/ WITH THE UNIT TURNED OFF MEASURE THE VOLTAGE YOU SHOULD HAVE APPROX 5V IF NOT THE CAP IS BAD. ALSO MEASURE WITH UNIT ON AND YOU SHOULD ALSO MEASURE 5 V IF NOT THEN THE SUPPLY VOLTAGE GOING TO THE CAP IS BAD.

The chances are that you have selected an incorrect sound setting or not switched it on, for the HDMI you are using. With Onkyo receivers each connection will have it own settings for video and sound. You just need to look in the manual as to how to select the settings.

I realize you may have already doubled checked but make sure you follow this from the manual:
If the satellite tuner / cable box is equipped with an S video output
terminal, connect it to the S VIDEO 3 (or 4) IN terminal with an S
video cable. If it does not have an S video output terminal, connect
its video output terminal to the VIDEO 3 (or 4) IN terminal using an
RCA-type video connection cable. You do not need to connect to
both the S VIDEO 3 (or 4) IN and VIDEO 3 (or 4) IN terminals. If
the satellite tuner or television has component video outputs,
connect them to one of the COMPONENT VIDEO INPUT jacks.
With the initial settings of the TX-DS898, the VIDEO 3 and
VIDEO 4 input sources are set for the COMPONENT VIDEO
INPUT 2 jack.
If the video connection is made at COMPONENT VIDEO INPUT
1, this must be changed at the Setup menu: Input Setup → Video
Setup → Component Video (see page 35).
Using an RCA-type audio connection cable, connect the audio
output terminal on the satellite tuner or television to the same
VIDEO 3 (or 4) IN audio jacks on the TX-DS898. Make sure that
you properly connect the left channel to the L jack and the right
channel to the R jack.
If the device has a digital output jack as well, be sure to also connect
it to either a DIGITAL INPUT (COAXIAL) or DIGITAL INPUT
(OPTICAL) jack on the TX-DS898 depending on the device.
With the initial settings of the TX-DS898, the VIDEO 3 input source
is set for digital input at the OPTICAL 3 jack, and the VIDEO 4
input source is set for digital input at the OPTICAL 4 jack.
If the digital connection is made at a different jack, this must be changed
at the Setup menu: Input Setup → Digital Setup (see page 33).

did the AS amp ever work properly from the RCA's?

Most of the time its the amps that are bad and need changing. This will be transistors on heatsink in the reciever. Part number should be on the amp.

check digital controll board

check speaker fuses.