diff --git a/src/mame/video/pc9801.cpp b/src/mame/video/pc9801.cpp
index 421bb6fc530..e421b995cd5 100644
--- a/src/mame/video/pc9801.cpp
+++ b/src/mame/video/pc9801.cpp
@@ -448,7 +448,7 @@ READ16_MEMBER(pc9801_state::tvram_r)
 	if((offset & 0x1000) && (mem_mask == 0xff00))
 		return 0xffff;
 
-	if(offset < (0x3fe0>>1))
+	if(offset < (0x3fe2>>1))
 		res = m_tvram[offset];
 	else
 		res = m_memsw->read(offset & 0xf);
@@ -458,10 +458,10 @@ READ16_MEMBER(pc9801_state::tvram_r)
 
 WRITE16_MEMBER(pc9801_state::tvram_w)
 {
-	if(offset < (0x3fe0>>1))
+	if(offset < (0x3fe2>>1))
 		COMBINE_DATA(&m_tvram[offset]);
-	else if(m_video_ff[MEMSW_REG])
-		m_memsw->write(offset & 0x0f, data);
+	else if(m_video_ff[MEMSW_REG] && ACCESSING_BITS_0_7)
+		m_memsw->write(offset & 0x0f, data & 0xff);
 
 	COMBINE_DATA(&m_video_ram_1[offset]); //TODO: check me
 }